subject:"Too narrowly defined\: DIVISION SIGN COLON"

The time to encode this ad-hoc symbol would arrive some time after 
others republish your proof *without* choosing a different symbol...at 
which point it would have become part of a convention.


A./

On 7/13/2012 5:20 AM, Julian Bradfield wrote:

On 2012-07-13, Michael Everson ever...@evertype.com wrote:

On 13 Jul 2012, at 11:07, Julian Bradfield wrote:
So... U+1D7CC MATHEMATICAL ITALIC SMALL MU NU LIGATURE, since it's published 
and (assuming the work is worthy; I cannot judge) might be cited by others.

It *might*, by some hapless master's student regurgitating the
proof. But that doesn't mean it should be encoded. It's an ad hoc
symbol, local to a particular series of papers (in so far as there is
a customary symbol, it's \sigma, but in that series of papers I needed
\sigma for another purpose), and within those papers, local to the
proof of particular theorems.
Anybody who reads the papers with understanding will realize that, and
therefore feel free to use any other symbol that is convenient to
them, if they don't feel like putting together a mu-nu symbol.
Once, I used $\mu \atop \nu$ (a small mu on top of a small nu) instead
-- that's in print too, in a very expensive book! Would you want to
encode that too?

If you're looking for more characters to encode, I'd rather see
COMBINING DOUBLE TILDE BELOW
which is used in Ladefoged and Maddieson, The Sounds of the World's
Language, to denote the strident vowels of Khoisan languages, and
which I therefore use in my work too.

Re: Too narrowly defined: DIVISION SIGN COLON


On 7/13/2012 3:07 AM, Julian Bradfield wrote:

My colleagues in the Edinburgh PEPA group did try to get their pet symbol 
encoded (a bowtie where the two triangles overlap somewhat rather than just 
touching), but were refused; although that symbol now appears in hundreds of 
papers by dozens of authors from all over the world.


If so, then it should be encoded.

The relevant person is on holiday at the moment, but I'll find out
from him the real story of the symbol. I think this was before the
supplementary planes opened up.


Please do.

A./

Re: Too narrowly defined: DIVISION SIGN COLON


On 7/13/2012 1:57 AM, Michael Everson wrote:
That document is 164 pages long. I would be interested in examining it 
after someone else has done the background work of a first pass at 
identifying which characters are already encoded. This is sort of an 
emoji/wingdings/webdings scenario, I guess. Michael Everson * 
http://www.evertype.com/ 


The process of encoding mathematical characters has used experts from a 
coalition of publishers to help make the differentiation between 
ad-hoc and conventional symbols. Only if there's a convention around 
the use of a symbol does it deserve encoding. If there's been a budding 
convention around some symbol (republication across other works) that 
was missed by this process, it would be nice to get access to this 
information from participants.


A./

PS: earlier versions of this document have been consulted in the process 
of completing the math repertoire

Re: Too narrowly defined: DIVISION SIGN COLON

2012-07-13 Thread Michael Everson

The TeX collection includes things which are not only mathematical symbols. No 
need to be so dismissive, Asmus.

On 13 Jul 2012, at 14:24, Asmus Freytag wrote:

 On 7/13/2012 1:57 AM, Michael Everson wrote:
 That document is 164 pages long. I would be interested in examining it after 
 someone else has done the background work of a first pass at identifying 
 which characters are already encoded. This is sort of an 
 emoji/wingdings/webdings scenario, I guess. Michael Everson * 
 http://www.evertype.com/ 
 
 The process of encoding mathematical characters has used experts from a 
 coalition of publishers to help make the differentiation between ad-hoc and 
 conventional symbols. Only if there's a convention around the use of a 
 symbol does it deserve encoding. If there's been a budding convention around 
 some symbol (republication across other works) that was missed by this 
 process, it would be nice to get access to this information from participants.
 
 A./
 
 PS: earlier versions of this document have been consulted in the process of 
 completing the math repertoire

Michael Everson * http://www.evertype.com/

More emoji - (was Re: Too narrowly defined: DIVISION SIGN COLON)

On 7/13/2012 6:37 AM, Michael Everson wrote:

The TeX collection includes things which are not only mathematical symbols. No
need to be so dismissive, Asmus.

No need to be so ... - my comment was carefully worded to apply
explicitly to mathematical usage only - and was issued in the context of
a discussion about mathematical symbols. Something as simple as a change
in subject line would have been sufficient to indicate that you were
after the emojis (or whatever) in that list, and that your comments were
not intended to apply to mathematical symbols.

For symbols of a more general sort the symbol list occupies an
interesting territory between a font showing and a character set. The
fact that the macros are individually named at a level accessible to the
end user, pushes it closer to a de-facto character set.

A./

On 13 Jul 2012, at 14:24, Asmus Freytag wrote:

On 7/13/2012 1:57 AM, Michael Everson wrote:

That document is 164 pages long. I would be interested in examining it after
someone else has done the background work of a first pass at identifying which
characters are already encoded. This is sort of an emoji/wingdings/webdings
scenario, I guess. Michael Everson * http://www.evertype.com/

The process of encoding mathematical characters has used experts from a coalition of publishers to
help make the differentiation between ad-hoc and conventional symbols. Only
if there's a convention around the use of a symbol does it deserve encoding. If there's been a
budding convention around some symbol (republication across other works) that was missed by this
process, it would be nice to get access to this information from participants.

A./

PS: earlier versions of this document have been consulted in the process of
completing the math repertoire

Michael Everson * http://www.evertype.com/

Re: Too narrowly defined: DIVISION SIGN COLON

[ Please don't copy me on replies; the place for this is the mailing
  list, not my inbox, unless you want to go off-list. ]

On 2012-07-11, Hans Aberg haber...@telia.com wrote:

Unicode has added all the characters from TeX plus some, making it
possible to use characters in the input file where TeX is forced to
use ASCII. This though changes the paradigm, and it is a question of
which paradigm one wants to adhere to. 

This doesn't seem to make much sense, or have much truth, to me.

TeX does not have a notion of character in the Unicode sense. TeX is a
(meta-)programming language for putting ink on paper. It ultimately
produces instructions of the form print glyph 42 from font cmr10 at
this position. It does not know or care whether the glyph happens to
be a representation of some Unicode character. (It also isn't tied to
ASCII for its input - when I first used TeX, it was on an EBCDIC
system.)

There are many characters that TeX users use that are not in
Unicode. Indeed, you can't even correctly represent the name of the
system in Unicode, or any other plain text system - an entirely
deliberate choice by Knuth to emphasise that TeX is a typesetting
program, not a text representation format.

Because TeX is agnostic about such matters, one can set up any
convenient encoding for the input data (which is really the source
code of a program). For example, I have written documents in ASCII,
Latin-1, Big5, GB, UTF-8 and probably others. This is very convenient;
but it's only a convenience.

If one uses UTF-8, then one has the problem of how to deal with the
case where Unicode trespasses on TeX's territory, by specifying font
styles. 
This is not hard: for example, the obvious thing to do is to
arrange for the Unicode MATHEMATICAL SMALL ITALIC M to be an
abbreviation for \mathit{m}, and so on.
Note, incidentally, that this is not the same as the meaning of a
plain ASCII (or EBCDIC) m in TeX. In TeX math mode, the meaning of
m is dependent on the currently selected math font family: just as
in plain text, the font of of m depends on the currently selected
text font.

One problem, of course, is that there is no MATHEMATICAL ROMAN set of
characters. This is one of the biggest botches in the whole
mathematical alphanumerical symbol botch. If you encode semantic font
distinctions without requiring the use of higher-level markup, then
you need to encode also letters that are semantically distinctively
roman upright. The square root of -1 cannot be italicized in the
statement of a theorem, unlike all the is that appear in the text of
the theorem. Yet Unicode provides no way to mark this semantic
distinction between the characters, and has to rely on the
higher-level markup distinguishing maths (to which some font style
changes should not be applied) from text (in which they should).

A more general problem is that which font styles are meaningful,
depends on the document. For example, I give lectures and talks, and I
set my slides in sans-serif. As I don't (usually) use distinctive
sans-serif symbols in my work, the maths is all in sans-serif
too: form, not content. But what then should I see if I type a Unicode
mathematical italic symbol in my slides? Serif, or sans-serif?

-- 
The University of Edinburgh is a charitable body, registered in
Scotland, with registration number SC005336.

Re: Too narrowly defined: DIVISION SIGN COLON

On 12 Jul 2012, at 10:44, Julian Bradfield wrote:

 [ Please don't copy me on replies; the place for this is the mailing
  list, not my inbox, unless you want to go off-list. ]

Check if you can set the mailing list preferences. On some lists, it is very 
important to cc, as those that post to the list may not be on the list, though 
that is not the case here.

 On 2012-07-11, Hans Aberg haber...@telia.com wrote:
 
 Unicode has added all the characters from TeX plus some, making it
 possible to use characters in the input file where TeX is forced to
 use ASCII. This though changes the paradigm, and it is a question of
 which paradigm one wants to adhere to. 
 
 This doesn't seem to make much sense, or have much truth, to me.
...
 There are many characters that TeX users use that are not in
 Unicode.

All standard characters from TeX, LaTeX, and AMSTeX should be there, and there 
are now STIXFonts http://stixfonts.org/ implementing them. In math, you can 
always invent your own characters and styles, in fact you could do that with 
any script, but it is not possible for Unicode to cover that. There are though 
a public use area, where one can add ones own characters.

 Because TeX is agnostic about such matters, one can set up any
 convenient encoding for the input data (which is really the source
 code of a program). For example, I have written documents in ASCII,
 Latin-1, Big5, GB, UTF-8 and probably others. This is very convenient;
 but it's only a convenience.

UTF-8 only is simplest for the programmer that has to implement it.

LuaTeX and the older XeTeX support UTF-8. They are available in TeX Live.
  http://www.tug.org/texlive/

 If one uses UTF-8, then one has the problem of how to deal with the
 case where Unicode trespasses on TeX's territory, by specifying font
 styles.
 This is not hard: for example, the obvious thing to do is to
 arrange for the Unicode MATHEMATICAL SMALL ITALIC M to be an
 abbreviation for \mathit{m}, and so on.
 Note, incidentally, that this is not the same as the meaning of a
 plain ASCII (or EBCDIC) m in TeX. In TeX math mode, the meaning of
 m is dependent on the currently selected math font family: just as
 in plain text, the font of of m depends on the currently selected
 text font.
 
 One problem, of course, is that there is no MATHEMATICAL ROMAN set of
 characters. This is one of the biggest botches in the whole
 mathematical alphanumerical symbol botch.

This was discussed here before; the LaTeX unicode-math package has options to 
control that (see its manual). For example, one gets a literal interpretation 
by:
  \usepackage[math-style=literal,colon=literal]{unicode-math}
  \defaultfontfeatures{Ligatures=TeX}
  \setmainfont{XITS}
  \setmathfont{XITS Math}

Here, the XITS fonts are used.
  http://www.khaledhosny.org/node/143

 If you encode semantic font
 distinctions without requiring the use of higher-level markup, then
 you need to encode also letters that are semantically distinctively
 roman upright.

It has already been encoded as mathematical style, see the Mathematical 
Alphanumeric Symbols here:
  http://www.unicode.org/charts/

And is available in STIX and the XITS fonts, plus some, as mentioned in the 
README of the before mentioned unicode-math package.

 A more general problem is that which font styles are meaningful,
 depends on the document. For example, I give lectures and talks, and I
 set my slides in sans-serif. As I don't (usually) use distinctive
 sans-serif symbols in my work, the maths is all in sans-serif
 too: form, not content. But what then should I see if I type a Unicode
 mathematical italic symbol in my slides? Serif, or sans-serif?

It is up to you. The unicode-package, mentioned above, has options to control 
that.

It is traditional in pure math, and also in the physics books have looked into, 
to always use serif. Possibly sanf-serif belongs to another technical style. 
Unicode makes it possible to mix these styles on the character level, if you so 
will.

Hans

Re: Too narrowly defined: DIVISION SIGN COLON

2012-07-12 Thread Joó Ádám

 [ Please don't copy me on replies; the place for this is the mailing
   list, not my inbox, unless you want to go off-list. ]

Hitting “reply to all” on your mail places you in the To field, and
the list in Cc. At least in Gmail.

Á

Re: Too narrowly defined: DIVISION SIGN COLON

On 12 Jul 2012, at 12:33, Julian Bradfield wrote:

 In practice, no working mathematician is going to use the mathematical
 alphanumerical symbols to write maths in (La)TeX, because it's
 fantastically inconvenient compared to the usual way (supplementary
 plane support is far from universal, and most publishers won't have
 the appropriate TeX unicode support; and as I've said in another post,
 the Unicode mathematical symbol model does not match how one uses
 mathematical symbols.

It is used by proof assistants such as Isabelle, and also in logic.
  https://en.wikipedia.org/wiki/Isabelle_(proof_assistant)

If your only objective is to achieve a rendering for humans to read, TeX is 
fine, but not if one wants to communicate semantic information on the computer 
level.

Hans

Re: Too narrowly defined: DIVISION SIGN COLON


2012-07-12 13:33, Julian Bradfield wrote:


On 2012-07-11, Eric Muller emul...@adobe.com wrote:

[…]

When it's plain text, Unicode has the burden of solving all the
problems. When it's a richer system, there is the issue of cooperation
between the layers, a situation that Unicode cannot ignore.


Unicode can ignore it - it's the lowest layer. It should leave the
problems entirely to the layers above it.


Things are not that simple. There are many distinctions that can be made 
at the plain text level or at some other level. Unicode gives the option 
of making many distinctions that could, and usually should, be made at a 
higher level. It simply gives e.g. the option of using mathematical 
sans-serif letters, without saying that anyone should use them. For 
example, when saving text in a database or sending text, you might be 
restricted to plain text for various reasons.



In practice, no working mathematician is going to use the mathematical
alphanumerical symbols to write maths in (La)TeX, because it's
fantastically inconvenient


Well, (La)TeX is a world of its own, and largely Unicode-ignorant on 
purpose, though there are some signs of taking Unicode seriously there 
(e.g. because many people want to be able to enter characters by their 
Unicode numbers).


In general, typing characters like mathematical sans-serif letters is 
awkward when using commonly used software with common keyboards and 
settings. But it need not be so. It would be easy to set up a keyboard 
layout where the “A” key produces mathematical sans serif a, another 
layout where it produces mathematical italic a, etc. (and switching 
between layouts can be simple, with keyboard shortcuts).


(I can’t imagine many situations where people would really want to 
*type* such characters, but if you are working in formula mode in Word, 
you might get puzzled when you need to type tensor symbols. The mode 
uses Cambria Math, and it does not let you change the font in any direct 
way, it seems. So the situation would really call for mathematical sans 
serif letters.)


Yucca

Re: Too narrowly defined: DIVISION SIGN COLON

On 2012-07-12, Hans Aberg haber...@telia.com wrote:
 There are many characters that TeX users use that are not in
 Unicode.

 All standard characters from TeX, LaTeX, and AMSTeX should be there,

What's a standard character? There's no such thing.
To take a random entry from the LaTeX Symbol Guide, where is the
\nrightspoon symbol from the MnSymbol package? (A negated multimap
symbol.)

Not to mention the symbols I've used from time to time, because

 them. In math, you can always invent your own characters and styles,

people do.

 in fact you could do that with any script, but it is not possible
 for Unicode to cover that. There are though a public use area, where
 one can add ones own characters. 

You mean private use. Crazy thing to do, because then you have to
worry about whether your PUA code point clashes with some other
author's PUA code point.

 Because TeX is agnostic about such matters, one can set up any
 convenient encoding for the input data (which is really the source
 code of a program). For example, I have written documents in ASCII,
 Latin-1, Big5, GB, UTF-8 and probably others. This is very convenient;
 but it's only a convenience.

 UTF-8 only is simplest for the programmer that has to implement it.

Some of us are more concerned with users than programmers. Beside, all
the work for the legacy encodings has already been done. I wouldn't
ever want to go back to ISO alphabet soup for Latin etc., but for
CJK, the legacy codings are still sometimes convenient - for example,
if I write in Big5, I don't have to worry about telling my editor to
find a traditional Chinese font rather than a simplified or japanese
font. It uses a Big5 font, and that's it.

 LuaTeX and the older XeTeX support UTF-8. They are available in TeX Live.
   http://www.tug.org/texlive/

They aren't TeX. Neither working mathematicians nor publishers nor
typesetters like dealing with constantly changing extensions and
variations on TeX - one of the biggest selling points of TeX is
stability. (Defeated somewhat by the instability of LaTeX and its
thousands of packages, but that's another story.)
If I need to write complex - or even bidi - scripts routinely, I'd
probably be forced into one of them; but the typical mathematician
doesn't.

 
 One problem, of course, is that there is no MATHEMATICAL ROMAN set of
 characters. This is one of the biggest botches in the whole
 mathematical alphanumerical symbol botch.

 This was discussed here before; the LaTeX unicode-math package has options to 
 control that (see its manual). For example, one gets a literal interpretation 
 by:

Exactly. TeX can do what it likes. But you said it was an incompatibility
with Unicode that TeX sets plain ASCII math letters as italic,
implying that TeX should not be allowed to do what it likes.

 If you encode semantic font
 distinctions without requiring the use of higher-level markup, then
 you need to encode also letters that are semantically distinctively
 roman upright.

 It has already been encoded as mathematical style, see the Mathematical 
 Alphanumeric Symbols here:
   http://www.unicode.org/charts/

*You* look. The plain upright style is unified with the BMP characters.

 A more general problem is that which font styles are meaningful,
 depends on the document. For example, I give lectures and talks, and I
 set my slides in sans-serif. As I don't (usually) use distinctive
 sans-serif symbols in my work, the maths is all in sans-serif
 too: form, not content. But what then should I see if I type a Unicode
 mathematical italic symbol in my slides? Serif, or sans-serif?


 It is up to you. The unicode-package, mentioned above, has options to control 
 that.

Of course it's up to me. I'm glad you agree. So why say that it's an
incompatibility with Unicode that TeX (by default) displays ASCII as
italic in maths? Are you changing your mind on that? I welcome that if
so, as that was what I found surprising.

(And, of course, it's much easier to use the established TeX
mechanisms for controlling these things, than to learn more options
for a package to allow me to use symbols that are hard to type and
even harder to distinguish clearly on screen.)

 It is traditional in pure math, and also in the physics books have looked 
 into, to always use serif. Possibly sanf-serif belongs to another technical 
 style. Unicode makes it possible to mix these styles on the character level, 
 if you so will.

It's also traditional, for mostly good reasons to do with the limited
resolution of projectors, to use sans-serif in presentations. The only
reason that most people still have serifed maths is that they don't
know how to do otherwise (\usepackage{cmbright} is enough for most
people, if only they knew).

-- 
The University of Edinburgh is a charitable body, registered in
Scotland, with registration number SC005336.

Re: Too narrowly defined: DIVISION SIGN COLON

On 2012-07-12, Hans Aberg haber...@telia.com wrote:
 On 12 Jul 2012, at 12:33, Julian Bradfield wrote:
 In practice, no working mathematician is going to use the mathematical
 alphanumerical symbols to write maths in (La)TeX, because it's
..
 the Unicode mathematical symbol model does not match how one uses
 mathematical symbols.

 It is used by proof assistants such as Isabelle, and also in logic.
   https://en.wikipedia.org/wiki/Isabelle_(proof_assistant)

No it isn't. Isabelle uses (essentially) TeX control sequences
internally, though it writes them as \oplus rather than \oplus .
A small number of these are mapped to Unicode code points for display
and input purposes, and that small number does not include any of the
mathematical alphanumerical symbols block.

 If your only objective is to achieve a rendering for humans to read, TeX is 
 fine, but not if one wants to communicate semantic information on the 
 computer level.

On the contrary, computers are very happy with TeX notation. There are
several useful mathematical online learning sites (such as, for
example, Alcumus) which use TeX syntax to interact with the students.


-- 
The University of Edinburgh is a charitable body, registered in
Scotland, with registration number SC005336.

Re: Too narrowly defined: DIVISION SIGN COLON

On 12 Jul 2012, at 15:54, Julian Bradfield wrote:

 On 2012-07-12, Hans Aberg haber...@telia.com wrote:
 There are many characters that TeX users use that are not in
 Unicode.
 
 All standard characters from TeX, LaTeX, and AMSTeX should be there,
 
 What's a standard character? There's no such thing.
 To take a random entry from the LaTeX Symbol Guide, where is the
 \nrightspoon symbol from the MnSymbol package? (A negated multimap
 symbol.)
 
 Not to mention the symbols I've used from time to time, because

You tell me, because I posted a request for missing characters in different 
forums. Perhaps you invented it after the standardization was made?

 them. In math, you can always invent your own characters and styles,
 
 people do.

You and others knowing about those characters must make proposals if you want 
to see them as a part of Unicode.

 in fact you could do that with any script, but it is not possible
 for Unicode to cover that. There are though a public use area, where
 one can add ones own characters. 
 
 You mean private use. Crazy thing to do, because then you have to
 worry about whether your PUA code point clashes with some other
 author's PUA code point.

There is some system for avoiding that. Perhaps someone else here can inform.

 Because TeX is agnostic about such matters, one can set up any
 convenient encoding for the input data (which is really the source
 code of a program). For example, I have written documents in ASCII,
 Latin-1, Big5, GB, UTF-8 and probably others. This is very convenient;
 but it's only a convenience.
 
 UTF-8 only is simplest for the programmer that has to implement it.
 
 Some of us are more concerned with users than programmers.

Well, if the programmers don't implement, you are left out in the cold.

 Beside, all
 the work for the legacy encodings has already been done. I wouldn't
 ever want to go back to ISO alphabet soup for Latin etc., but for
 CJK, the legacy codings are still sometimes convenient - for example,
 if I write in Big5, I don't have to worry about telling my editor to
 find a traditional Chinese font rather than a simplified or japanese
 font. It uses a Big5 font, and that's it.

Before UTF-8, in the 1990s, some Russians used multi-encoded text files with 
TeX/LaTeX, but I doubt they do that anymore. Use whatever you like.

 LuaTeX and the older XeTeX support UTF-8. They are available in TeX Live.
  http://www.tug.org/texlive/
 
 They aren't TeX.

Clearly not, since TeX is not developed anymore.

 Neither working mathematicians nor publishers nor
 typesetters like dealing with constantly changing extensions and
 variations on TeX - one of the biggest selling points of TeX is
 stability. (Defeated somewhat by the instability of LaTeX and its
 thousands of packages, but that's another story.)
 If I need to write complex - or even bidi - scripts routinely, I'd
 probably be forced into one of them; but the typical mathematician
 doesn't.

I do not see your point here.

 One problem, of course, is that there is no MATHEMATICAL ROMAN set of
 characters. This is one of the biggest botches in the whole
 mathematical alphanumerical symbol botch.
 
 This was discussed here before; the LaTeX unicode-math package has options 
 to control that (see its manual). For example, one gets a literal 
 interpretation by:
 
 Exactly. TeX can do what it likes.

No. TeX cannot handle UTF-8, and I recall LaTeX's capability to emulate that 
was limited.

 But you said it was an incompatibility
 with Unicode that TeX sets plain ASCII math letters as italic,
 implying that TeX should not be allowed to do what it likes.

In LuaTeX or XeTeX, it is obviously relative the original TeX definitions, 
those that most are used to.

 If you encode semantic font
 distinctions without requiring the use of higher-level markup, then
 you need to encode also letters that are semantically distinctively
 roman upright.
 
 It has already been encoded as mathematical style, see the Mathematical 
 Alphanumeric Symbols here:
  http://www.unicode.org/charts/
 
 *You* look. The plain upright style is unified with the BMP characters.

Yes, that is why the Unicode paradigm departs from the TeX one.

 A more general problem is that which font styles are meaningful,
 depends on the document. For example, I give lectures and talks, and I
 set my slides in sans-serif. As I don't (usually) use distinctive
 sans-serif symbols in my work, the maths is all in sans-serif
 too: form, not content. But what then should I see if I type a Unicode
 mathematical italic symbol in my slides? Serif, or sans-serif?
 
 
 It is up to you. The unicode-package, mentioned above, has options to 
 control that.
 
 Of course it's up to me. I'm glad you agree. So why say that it's an
 incompatibility with Unicode that TeX (by default) displays ASCII as
 italic in maths? Are you changing your mind on that? I welcome that if
 so, as that was what I found surprising.

You have yourself noted that the BMP characters must

Re: Too narrowly defined: DIVISION SIGN COLON


On 7/10/2012 5:35 PM, Mark Davis ☕ wrote:
The main point is that asserting a general preference in an annotation 
for ∶ to express a ratio, as Asmus had in his formulation, is simply 
wrong and counterproductive. (We are not going to change the world's 
usage from : to ∶ by fiat; and and the glyphic difference is quite 
subtle, and missing in a great many fonts. Compare that with the 
difference between hyphen-minus and minus, which is much more 
pronounced, and much better carried across fonts.)


The most that we could say is that in certain mathematical contexts ∶ 
is preferred to : for expressing ratios, not that it is generally 
preferred.





I don't see any problem in amending the proposed annotations

U+003A COLON
* also used to denote division or scale, for that usage 2236 : RATIO is 
preferred in mathematical use

U+2236 RATIO
* Used in preference to 003A : to denote division or scale in 
mathematical use


however, like the use of curly quotes over straight quotes, certain 
preferences do apply for high-end typography irrespective of whether 
fallback characters are or are not widely used for lower quality 
documents.


A./

Re: Too narrowly defined: DIVISION SIGN COLON

On 12 Jul 2012, at 16:06, Julian Bradfield wrote:

 On 2012-07-12, Hans Aberg haber...@telia.com wrote:
 On 12 Jul 2012, at 12:33, Julian Bradfield wrote:
 In practice, no working mathematician is going to use the mathematical
 alphanumerical symbols to write maths in (La)TeX, because it's
 ..
 the Unicode mathematical symbol model does not match how one uses
 mathematical symbols.
 
 It is used by proof assistants such as Isabelle, and also in logic.
  https://en.wikipedia.org/wiki/Isabelle_(proof_assistant)
 
 No it isn't.

Yes, I posted before here some example of people using it.

 Isabelle uses (essentially) TeX control sequences
 internally, though it writes them as \oplus rather than \oplus .
 A small number of these are mapped to Unicode code points for display
 and input purposes, and that small number does not include any of the
 mathematical alphanumerical symbols block.

Latest version requires STIXFonts to be installed. Some other proof assistants 
use it.

 If your only objective is to achieve a rendering for humans to read, TeX is 
 fine, but not if one wants to communicate semantic information on the 
 computer level.
 
 On the contrary, computers are very happy with TeX notation. There are
 several useful mathematical online learning sites (such as, for
 example, Alcumus) which use TeX syntax to interact with the students.

TeX formulas are just for rendering. For example, if you want to have 
superscript to the left, you have to write ${}^x y$.

Hans

Re: Too narrowly defined: DIVISION SIGN COLON

Title: HTML clipboard

  
  

Here's my *updated* summary of the annotations that we've been
  discussing so far:
  
  U+003A COLON
  * also used to denote division or scale, for that usage 2236 :
  RATIO is preferred in mathematical use
  
  U+00B7 MIDDLE DOT
  * also used as raised decimal point or to denote multiplication,
  for the latter usage 22C5 · DOT OPERATOR is preferred
  
  U+2052 COMMERCIAL MINUS SIGN
  x 00F7 division sign
  
  U+22C5 DOT OPERATOR
  * Used in preference to 00B7 · to denote multiplication
  
  U+2236 RATIO
  * Used in preference to 003A : to denote division or scale in
  mathematical use
  
  U+00F7 DIVISION SIGN
  = obelus
  * also used as an alternate, more visually distinct 2212 - MINUS
  SIGN or 2011 – EN DASH in some contexts
  * historically used as a punctuation mark to denote questionable
  passages in manuscripts
  x 070B syriac harklean obelus
  x 2212 minus sign
  x 2052 commercial minus sign
  x 2236 ratio 


  (the reference to en-dash is based on the Italian usage cited in
  the Wikipedia article for Obelus)
  
  
  The discussion of these symbols in the relevant chapters of the
  standard could also be improved.
  
  On page 200, the subsection "Other Punctuation" should be
  augmented by this sub-sub-section
  
  /Obelus/ Originally a punctuation mark to denote questionable
  passages in manuscripts, U+00F7 DIVISION SIGN is now most commonly
  used as a symbol indicating division. However, even modern use is
  not limited to that meaning. The character can be found as
  indicating a range (similar to the /en-dash/) or as a form of
  /minus sign/. The former use is attested for Russian, Polish and
  Italian and latter use is still widespread in Scandinavian
  countries in some contexts, but may occur elsewhere as well. (see
  also "Commercial Minus").
[for background documentation for the above passage see:
  http://www.unicode.org/mail-arch/unicode-ml/y2012-m07/0134.html]
  
  On page 203 after "Scandinavia" add "(see also Obelus)".
  
  On page 202 of chapter 6 add under "Other..."
  
  Several punctuation marks, such as COLON, MIDDLE DOT and SOLIDUS
  closely resemble mathematical operators, such as U+2236 RATIO,
  U+22xx DOT OPERATOR and U+22xx DIVISION SLASH. The latter are the
  preferred characters, but the former, being more easily typed, are
  often substituted.
  
  On page 511 of chapter 15 add in "Semantics" after "context".
  
  "For some common mathematical symbols there are also local
  variations in usage. For example, U+00D7 DIVISION SIGN, besides
  having a long history of use as punctuation mark, is also used in
  certain cases to indicate negative numbers in several European
  countries."
  
  It might be worth mentioning U+00D7 MULTIPLICATION SIGN in chapter
  15.5, because it's arguably a mathematical operator, even though
  not encoded in the standard blocks of operators.
  
  /Mathematical Operators In other Blocks/
  
  A small number of mathematical operators and related characters in
  common use have been encoded in other blocks. These include U+002B
  PLUS SIGN, U+00D7 MULTIPLICATION SIGN and U+00F7 DIVISION SIGN, as
  well as 003C GREATER THAN, 003D EQUALS SIGN and 003E LESS THAN.
  The /factorial operator / is unified with U+0021 EXCLAMATION MARK
  
  In Chapter 15.5, add this table after /Unifications/ on page 512
  
  Table 15-xxx
  
  Mathematical Operators Disunified from Punctuation
  
  002D - HYPHEN-MINUS
  2212 − MINUS SIGN
  
  003F / SOLIDUS or /slash/
  2215 ∕ DIVISION SLASH
  
  005C \ REVERSE SOLIDUS or /backslash/
  2216 ∖ SET MINUS
  
  002A * ASTERISK
  2217 ∗ ASTERISK OPERATOR
  
  25E6 ◦ WHITE BULLET
  2218 ∘ RING OPERATOR
  
  2022 • BULLET
  2219 ∙ BULLET OPERATOR
  
  007C | VERTICAL BAR
  2223 ∣ DIVIDES
  
  2016 ‖ DOUBLE VERTICAL BAR
  2225 ∥ PARALLEL TO
  
  003A : COLON
  2236 ∶ RATIO
  
  007E ~ TILDE
  22C3 ∼ TILDE OPERATOR
  
  00B7 · MIDDLE DOT
  22C5 ⋅ DOT OPERATOR
  [My mailer makes huge gaps between paragraphs - where mathematical
  fonts are used - the intent is to have three columns, CODE, GLYPH,
  NAME and each table row containing two rows of text (i.e. the pair
  of characters).]
  
  /Disunifications/ A number of mathematical operators 
  have been disunified form related or similar punctuation 
  characters (see table 15-xx). In addition to allowing the
  encode of specifically mathematical semantics, there are
  some display differences. Math operators render

Re: Too narrowly defined: DIVISION SIGN COLON


2012-07-12 19:31, Asmus Freytag wrote:


I don't see any problem in amending the proposed annotations

U+003A COLON
* also used to denote division or scale, for that usage 2236 : RATIO is
preferred in mathematical use
U+2236 RATIO
* Used in preference to 003A : to denote division or scale in
mathematical use


I see a big problem here: why would the Unicode Standard take a position 
on mathematical use in a manner that strongly conflicts with the ISO and 
IEC standard on mathematical notations? The ISO 8-2 standard (also 
issued as IEC standard) designates U+003A as a character used for ratios.


What I have proposed, regarding COLON, is just

* also used to denote division or ratio

I don’t think RATIO needs an annotation, as the name reflects the 
intended usage. But if an annotation is added, it could be e.g.


* used to denote ratio (e.g. in a scale), as an alternative to 003A COLON

Yucca

Re: Too narrowly defined: DIVISION SIGN COLON

On 12 Jul 2012, at 19:24, Jukka K. Korpela wrote:

 2012-07-12 19:31, Asmus Freytag wrote:
 
 I don't see any problem in amending the proposed annotations
 
 U+003A COLON
 * also used to denote division or scale, for that usage 2236 : RATIO is
 preferred in mathematical use
 U+2236 RATIO
 * Used in preference to 003A : to denote division or scale in
 mathematical use
 
 I see a big problem here: why would the Unicode Standard take a position on 
 mathematical use in a manner that strongly conflicts with the ISO and IEC 
 standard on mathematical notations? The ISO 8-2 standard (also issued as 
 IEC standard) designates U+003A as a character used for ratios.

The glyphs might be typeset differently with respect to fonts. So those should 
be hints as to what use in a mathematical context.

Hans

Re: Too narrowly defined: DIVISION SIGN COLON


2012-07-12 20:23, Asmus Freytag wrote:


U+00B7 MIDDLE DOT
* also used as raised decimal point or to denote multiplication, for the
latter usage 22C5 · DOT OPERATOR is preferred


Is there evidence of actual use of MIDDLE DOT as decimal point? I mean 
the use of the Unicode character, rather than PERIOD raised using 
higher-level protocols.


Even if there is, it would perhaps be a bit odd to mention two usages 
and make a normative statement on one of them but not the other. I think 
relevant standards take it for granted that when a decimal point is 
used, it is FULL STOP, and the Unicode Standard (p. 201) seems to agree:


“In contrast, the various functions of the period, such as its use as 
sentence-ending punctuation, an abbreviation mark, or a decimal point, 
are not separately encoded. The specific semantic therefore depends on 
context.”


Yucca

Re: Too narrowly defined: DIVISION SIGN COLON


On 7/12/2012 10:24 AM, Jukka K. Korpela wrote:

2012-07-12 19:31, Asmus Freytag wrote:


I don't see any problem in amending the proposed annotations

U+003A COLON
* also used to denote division or scale, for that usage 2236 : RATIO is
preferred in mathematical use
U+2236 RATIO
* Used in preference to 003A : to denote division or scale in
mathematical use


I see a big problem here: why would the Unicode Standard take a 
position on mathematical use in a manner that strongly conflicts with 
the ISO and IEC standard on mathematical notations? The ISO 8-2 
standard (also issued as IEC standard) designates U+003A as a 
character used for ratios.


What the examples show from TeX is that colon and ratio cannot be 
substituted for each other without affecting the display. The best that 
you can do with colon is to type SPACE COLON SPACE to get the correct 
display for an operator.


I have no opinion on ISO 8-2, but if this example is typical, I 
don't think much of the quality of that standard.


A./



What I have proposed, regarding COLON, is just

* also used to denote division or ratio

I don’t think RATIO needs an annotation, as the name reflects the 
intended usage. But if an annotation is added, it could be e.g.


* used to denote ratio (e.g. in a scale), as an alternative to 003A COLON

Yucca

Re: Too narrowly defined: DIVISION SIGN COLON

On 12 Jul 2012, at 19:02, Jukka K. Korpela wrote:

 Is there evidence of actual use of MIDDLE DOT as decimal point? I mean the 
 use of the Unicode character, rather than PERIOD raised using higher-level 
 protocols.

I have evidence of a very high dot used as a thousands separator. I am not sure 
if this dot has been encoded.

Michael Everson * http://www.evertype.com/

Re: Too narrowly defined: DIVISION SIGN COLON

2012-07-12 Thread Philippe Verdy

2012/7/12 Michael Everson ever...@evertype.com:
 On 12 Jul 2012, at 19:02, Jukka K. Korpela wrote:

 Is there evidence of actual use of MIDDLE DOT as decimal point? I mean the 
 use of the Unicode character, rather than PERIOD raised using higher-level 
 protocols.

 I have evidence of a very high dot used as a thousands separator. I am not 
 sure if this dot has been encoded.

Wasn't it a small vertical quote ? The evidences using the ASCII
single quote mark are easy to find.

I've also occasionnaly seen a small raised tack and a small caron
(both were centered on the height of digits, i.e. with parts slightly
above), possibly as more visible variants of quote-like marks.

Re: Too narrowly defined: DIVISION SIGN COLON


2012-07-12 21:07, Asmus Freytag wrote:


What the examples show from TeX is that colon and ratio cannot be
substituted for each other without affecting the display.


This looks like a problem in TeX rather than character standards. If TeX 
can space $a+b$ properly, what’s the issue with $a:b$? And when I tested 
it, I got proper spacing, corresponding to the example in 
“Detailtypographie” (which mentions that the colon, Doppelpunkt, is used 
“eventuell aus didaktischen Gründen, sonst eher veraltet oder als 
»verhält sic zu« verwendet”).


However, it might be argued that disambiguation is desirable, because 
COLON is also used as punctuation symbol in mathematical expressions, as 
in “f: A → B” and here (arguably) there should be some spacing after the 
colon but not before it. Yet, there are other contexts where the meaning 
of a symbol should affect is spacing in math, and yet we don’t have 
specialized symbols for them. (For example, the vertical bar should 
probably have different spacing when used for an absolute value, as in 
|a|, and when used as a separator as in {x|x²1}, but this must be 
handled by special logic in typesetting software or, more reasonably, by 
using spaces and/or formatting tools.)



I have no opinion on ISO 8-2, but if this example is typical, I
don't think much of the quality of that standard.


It’s about notations, not typography, and it has some flaws, but I don’t 
see an issue here.


Yucca

Re: Too narrowly defined: DIVISION SIGN COLON

On 12 Jul 2012, at 21:03, Jukka K. Korpela wrote:

 2012-07-12 21:07, Asmus Freytag wrote:
 
 What the examples show from TeX is that colon and ratio cannot be
 substituted for each other without affecting the display.
 
 This looks like a problem in TeX rather than character standards. If TeX can 
 space $a+b$ properly, what’s the issue with $a:b$? And when I tested it, I 
 got proper spacing, corresponding to the example in “Detailtypographie” 
 (which mentions that the colon, Doppelpunkt, is used “eventuell aus 
 didaktischen Gründen, sonst eher veraltet oder als »verhält sic zu« 
 verwendet”).
 
 However, it might be argued that disambiguation is desirable, because COLON 
 is also used as punctuation symbol in mathematical expressions, as in “f: A → 
 B” and here (arguably) there should be some spacing after the colon but not 
 before it.

In original TeX, there should be $a:b$ and $f\colon A \rightarrow B$. If you 
want to use Unicode characters, it is possible with (compiled with lualatex):
\documentclass{article}
\usepackage{amsmath}

\usepackage{fontspec}
\usepackage[math-style=literal,colon=literal]{unicode-math}

\defaultfontfeatures{Ligatures=TeX}

\setmainfont{XITS}
\setmathfont{XITS Math}

\begin{document}
$f: A → 푩, 퐁, B, 헕, 혽$ and $a∶b$.
\end{document}

Here, colon=literal causes the two colon types behave as marked in Unicode, and 
math-style=literal causes the same for the mathematical semantic styles.

Hans

Re: Too narrowly defined: DIVISION SIGN COLON

Hans wrote:
On 12 Jul 2012, at 15:54, Julian Bradfield wrote:
..
 Not to mention the symbols I've used from time to time, because

You tell me, because I posted a request for missing characters in different 
forums. Perhaps you invented it after the standardization was made?

Why on earth would I care about whether my pet symbol (a mu-nu
ligature, which I started using to stand for mu or nu as appropriate
when I ran out of other plausible letters for it) is in Unicode? It
would be crazy to put it there, and of precious little benefit to me,
since I don't wish to write web pages about this stuff.

 them. In math, you can always invent your own characters and styles,
 people do.
You and others knowing about those characters must make proposals if you want 
to see them as a part of Unicode.

But wanting to do so would be crazy. My mu-nu ligature is, as far as I
know, used only by me (and co-authors who let me do the typesetting),
and so if Unicode has any sanity left, it would not encode it. My
colleagues in the Edinburgh PEPA group did try to get their pet symbol
encoded (a bowtie where the two triangles overlap somewhat rather than
just touching), but were refused; although that symbol now appears in
hundreds of papers by dozens of authors from all over the world. (I
think they wanted it so they could put it on web pages, which they
have lots of.)

Putting a symbol into Unicode imposes a huge burden on thousands of
people. Everybody who thinks it important to be able to display all
Unicode characters (or even all non-Han characters) has to make sure
that their font has it, or that the distribution they package has it,
or that all the software in the world knows how to find a font that
has it. Such effort is entirely inappropriate for symbols used ad hoc
by a small community, who are communicating in any case via either
fully typeset documents or by TeX pseudocode - or, on occasion, with
real TeX and a suitable font definition.

 You mean private use. Crazy thing to do, because then you have to
 worry about whether your PUA code point clashes with some other
 author's PUA code point.

There is some system for avoiding that. Perhaps someone else here can inform.

There are many such systems - I don't need help or advice on this
matter. But none of them is appropriate for a symbol that perhaps you
want only for a few papers.

 UTF-8 only is simplest for the programmer that has to implement it.
 Some of us are more concerned with users than programmers.
Well, if the programmers don't implement, you are left out in the cold.

I'm not - if I care enough, I'll do it myself. Although most of my
work has actually been implementing utf-8 - as I said, the legacy
encodings are usually already done.

 Neither working mathematicians nor publishers nor
 typesetters like dealing with constantly changing extensions and
 variations on TeX - one of the biggest selling points of TeX is
 stability. (Defeated somewhat by the instability of LaTeX and its
 thousands of packages, but that's another story.)
 If I need to write complex - or even bidi - scripts routinely, I'd
 probably be forced into one of them; but the typical mathematician
 doesn't.

I do not see your point here.

The point is that you don't use unstable rapidly changing systems for
anything that has an expected life of more than a year or two; and if
you're planning for somebody else to use it, you try to give them
something that runs on systems at least ten years older than yours.

No. TeX cannot handle UTF-8, and I recall LaTeX's capability to emulate that 
was limited.

Somewhat limited, but good enough for every purpose I've so far needed
(maths, phonetics; and European, Indic, Chinese, Hebrew languages in
small snippets rather than entire documents). The main annoyance is
that combining character support is clunky, and that TeX really
doesn't support bidi properly - as I said - though it's remarkable
what hacking can be done.

 you need to encode also letters that are semantically distinctively
 roman upright.
 
 It has already been encoded as mathematical style, see the Mathematical 
 Alphanumeric Symbols here:
  http://www.unicode.org/charts/
 
 *You* look. The plain upright style is unified with the BMP characters.

Yes, that is why the Unicode paradigm departs from the TeX one.

This is as bad as Naena Guru... Unicode characters are
fontless. They are plain text. The Unicode standard even has a
nice little picture (Figure 2-2) showing how roman A, squashed A, bold
italic A, script A, fancy A, sans-serif A, brush-stroke A, fancy
script A, and versal capital A are all just LATIN LETTER A.

Now, in response to the desire of some mathematicians (maybe) to
write webpages without having to use clunky HTML markup (which is even
worse to use than TeX's), Unicode saw fit to encode characters such as
MATHEMATICAL BOLD ITALIC CAPITAL A.
This is not a logical problem: that character is distinguished from
LATIN LETTER A by the fact that its acceptable glyph variants

Re: Too narrowly defined: DIVISION SIGN COLON

On 12 Jul 2012, at 22:20, Julian Bradfield wrote:

 But wanting to do so would be crazy. My mu-nu ligature is, as far as I know, 
 used only by me (and co-authors who let me do the typesetting), and so if 
 Unicode has any sanity left, it would not encode it.

Is it in print? 

 My colleagues in the Edinburgh PEPA group did try to get their pet symbol 
 encoded (a bowtie where the two triangles overlap somewhat rather than just 
 touching), but were refused; although that symbol now appears in hundreds of 
 papers by dozens of authors from all over the world.

If so, then it should be encoded. 

Michael Everson * http://www.evertype.com/

Re: Too narrowly defined: DIVISION SIGN COLON

On 2012-07-12, Hans Aberg haber...@telia.com wrote:
On 12 Jul 2012, at 16:06, Julian Bradfield wrote:
 On 2012-07-12, Hans Aberg haber...@telia.com wrote:
 On 12 Jul 2012, at 12:33, Julian Bradfield wrote:
 In practice, no working mathematician is going to use the mathematical
 alphanumerical symbols to write maths in (La)TeX, because it's
 ..
 the Unicode mathematical symbol model does not match how one uses
 mathematical symbols.
 
 It is used by proof assistants such as Isabelle, and also in logic.
  https://en.wikipedia.org/wiki/Isabelle_(proof_assistant)
 
 No it isn't.

Yes, I posted before here some example of people using it.

I beg your pardon, you're right. I didn't read it closely enough.

 Isabelle uses (essentially) TeX control sequences
 internally, though it writes them as \oplus rather than \oplus .
 A small number of these are mapped to Unicode code points for display
 and input purposes, and that small number does not include any of the
 mathematical alphanumerical symbols block.

You're right, it does default to using that block in Unicode mode.

Latest version requires STIXFonts to be installed. Some other proof assistants 
use it.

However, that's not true. Isabelle does not need to use Unicode; it
runs happily in an ASCII terminal, because its internal representation
is tokens, not Unicode characters. The Unicode is syntactic sugar
that's part of the Emacs interface and the Scala interface.

 If your only objective is to achieve a rendering for humans to read, TeX is 
 fine, but not if one wants to communicate semantic information on the 
 computer level.
 
 On the contrary, computers are very happy with TeX notation. There are
 several useful mathematical online learning sites (such as, for
 example, Alcumus) which use TeX syntax to interact with the students.

TeX formulas are just for rendering. For example, if you want to have 
superscript to the left, you have to write ${}^x y$.

If you read any introduction to TeX, it will explain how you use
macros to provide a structured markup. If you were using that
notation, then you would define a suitable macro, say 
\def\tetration#1#2{{}^{#2}{#1}}
and write $\tetration{y}{x}$.
This does not depend on any fancy Unicodery for its interpretation,
and also allows you to define semantic content for the computer.

-- 
The University of Edinburgh is a charitable body, registered in
Scotland, with registration number SC005336.

Re: Too narrowly defined: DIVISION SIGN COLON

On 12 Jul 2012, at 23:20, Julian Bradfield wrote:

[If yo do not send an email directly to me, I may overlook seeing it, due to my 
filtering system.]

 Hans wrote:
 On 12 Jul 2012, at 15:54, Julian Bradfield wrote:
 ..
 Not to mention the symbols I've used from time to time, because
 
 You tell me, because I posted a request for missing characters in different 
 forums. Perhaps you invented it after the standardization was made?
 
 Why on earth would I care about whether my pet symbol (a mu-nu
 ligature, which I started using to stand for mu or nu as appropriate
 when I ran out of other plausible letters for it) is in Unicode? It
 would be crazy to put it there, and of precious little benefit to me,
 since I don't wish to write web pages about this stuff.

Well, this list about Unicode, so the issue is off-topic then.

 them. In math, you can always invent your own characters and styles,
 people do.
 You and others knowing about those characters must make proposals if you 
 want to see them as a part of Unicode.
 
 But wanting to do so would be crazy. My mu-nu ligature is, as far as I
 know, used only by me (and co-authors who let me do the typesetting),
 and so if Unicode has any sanity left, it would not encode it. My
 colleagues in the Edinburgh PEPA group did try to get their pet symbol
 encoded (a bowtie where the two triangles overlap somewhat rather than
 just touching), but were refused; although that symbol now appears in
 hundreds of papers by dozens of authors from all over the world. (I
 think they wanted it so they could put it on web pages, which they
 have lots of.)

Perhaps they should give another try, if now that there is wider support for 
its usage.

 Putting a symbol into Unicode imposes a huge burden on thousands of
 people. Everybody who thinks it important to be able to display all
 Unicode characters (or even all non-Han characters) has to make sure
 that their font has it, or that the distribution they package has it,
 or that all the software in the world knows how to find a font that
 has it. Such effort is entirely inappropriate for symbols used ad hoc
 by a small community, who are communicating in any case via either
 fully typeset documents or by TeX pseudocode - or, on occasion, with
 real TeX and a suitable font definition.

For that, there is the private use area. But it is up them if they find it 
useful.

 You mean private use. Crazy thing to do, because then you have to
 worry about whether your PUA code point clashes with some other
 author's PUA code point.
 
 There is some system for avoiding that. Perhaps someone else here can inform.
 
 There are many such systems - I don't need help or advice on this
 matter. But none of them is appropriate for a symbol that perhaps you
 want only for a few papers.

Perhaps you should address that issue to the consortium, if you deem it 
important to you.

 UTF-8 only is simplest for the programmer that has to implement it.
 Some of us are more concerned with users than programmers.
 Well, if the programmers don't implement, you are left out in the cold.
 
 I'm not - if I care enough, I'll do it myself. Although most of my
 work has actually been implementing utf-8 - as I said, the legacy
 encodings are usually already done.

The support for various encodings in LaTeX2 was a teamwork, and required so 
much work, they nearly lost focus on the typesetting issues.

 Neither working mathematicians nor publishers nor
 typesetters like dealing with constantly changing extensions and
 variations on TeX - one of the biggest selling points of TeX is
 stability. (Defeated somewhat by the instability of LaTeX and its
 thousands of packages, but that's another story.)
 If I need to write complex - or even bidi - scripts routinely, I'd
 probably be forced into one of them; but the typical mathematician
 doesn't.
 
 I do not see your point here.
 
 The point is that you don't use unstable rapidly changing systems for
 anything that has an expected life of more than a year or two; and if
 you're planning for somebody else to use it, you try to give them
 something that runs on systems at least ten years older than yours.

There are different strategies with respect to how updated software to use.

 No. TeX cannot handle UTF-8, and I recall LaTeX's capability to emulate that 
 was limited.
 
 Somewhat limited, but good enough for every purpose I've so far needed
 (maths, phonetics; and European, Indic, Chinese, Hebrew languages in
 small snippets rather than entire documents). The main annoyance is
 that combining character support is clunky, and that TeX really
 doesn't support bidi properly - as I said - though it's remarkable
 what hacking can be done.

It was after doing such hacking for a decade or two that the other systems were 
developed.

 you need to encode also letters that are semantically distinctively
 roman upright.
 
 It has already been encoded as mathematical style, see the Mathematical 
 Alphanumeric Symbols here:

Re: Too narrowly defined: DIVISION SIGN COLON

On 12 Jul 2012, at 23:47, Michael Everson wrote:
...
 Is it in print? 
...
 If so, then it should be encoded. 

There is a document The Comprehensive LaTeX Symbol List with a lot symbols. 
In my installation from TeX Live http://www.tug.org/texlive/, it is in:
  /usr/local/texlive/2012/texmf-dist/doc/latex/comprehensive/symbols-a4.pdf
  /usr/local/texlive/2012/texmf-dist/doc/latex/comprehensive/symbols-letter.pd

There could be another collation row.

Hans

Re: Too narrowly defined: DIVISION SIGN COLON


On 12 Jul 2012, at 23:27, Hans Aberg wrote:

 On 12 Jul 2012, at 23:47, Michael Everson wrote:
 ...
 Is it in print? 
 ...
 If so, then it should be encoded. 
 
 There is a document The Comprehensive LaTeX Symbol List with a lot symbols. 
 In my installation from TeX Live http://www.tug.org/texlive/, it is in:
  /usr/local/texlive/2012/texmf-dist/doc/latex/comprehensive/symbols-a4.pdf
  /usr/local/texlive/2012/texmf-dist/doc/latex/comprehensive/symbols-letter.pd

Local documents on your computer don't do me any good.

But what I meant was Is it in print in the real world? Not just in TeX 
documentation.

Still it might be interesting to see the symbols-a4.pdf.

Michael Everson * http://www.evertype.com/

Re: Too narrowly defined: DIVISION SIGN COLON


On 12 Jul 2012, at 23:27, Hans Aberg wrote:

 On 12 Jul 2012, at 23:47, Michael Everson wrote:
 ...
 Is it in print? 
 ...
 If so, then it should be encoded. 
 
 There is a document The Comprehensive LaTeX Symbol List with a lot symbols. 
 In my installation from TeX Live http://www.tug.org/texlive/, it is in:
  /usr/local/texlive/2012/texmf-dist/doc/latex/comprehensive/symbols-a4.pdf
  /usr/local/texlive/2012/texmf-dist/doc/latex/comprehensive/symbols-letter.pd


Is it 
http://www.tex.ac.uk/tex-archive/info/symbols/comprehensive/symbols-a4.pdf ?

Michael Everson * http://www.evertype.com/

Re: Too narrowly defined: DIVISION SIGN COLON

On 13 Jul 2012, at 00:10, Julian Bradfield wrote:

 Latest version requires STIXFonts to be installed. Some other proof 
 assistants use it.
 
 However, that's not true. Isabelle does not need to use Unicode; it
 runs happily in an ASCII terminal, because its internal representation
 is tokens, not Unicode characters. The Unicode is syntactic sugar
 that's part of the Emacs interface and the Scala interface.

I did not check the details, only noting that it will install them.

 If your only objective is to achieve a rendering for humans to read, TeX 
 is fine, but not if one wants to communicate semantic information on the 
 computer level.
 
 On the contrary, computers are very happy with TeX notation. There are
 several useful mathematical online learning sites (such as, for
 example, Alcumus) which use TeX syntax to interact with the students.
 
 TeX formulas are just for rendering. For example, if you want to have 
 superscript to the left, you have to write ${}^x y$.
 
 If you read any introduction to TeX, it will explain how you use
 macros to provide a structured markup. If you were using that
 notation, then you would define a suitable macro, say 
 \def\tetration#1#2{{}^{#2}{#1}}
 and write $\tetration{y}{x}$.
 This does not depend on any fancy Unicodery for its interpretation,
 and also allows you to define semantic content for the computer.

TeX does not parse the formulas. It cannot see the operator precedences in an 
expression like a + b*c. It just renders it. The program you mentioned seems to 
not use TeX, but is another computer program using TeX-like syntax (it looked 
it departed from strict TeX).

Hans

Re: Too narrowly defined: DIVISION SIGN COLON

On 12 Jul 2012, at 19:23, Asmus Freytag wrote:

 Here's my *updated* summary of the annotations that we've been discussing so 
 far:
 
 U+003A COLON
 * also used to denote division or scale, for that usage 2236 : RATIO is 
 preferred in mathematical use

Perhaps the mathematical styles that exists in both upright and italics should 
have it mentioned that the former might be preferred for constants and the 
latter for variables. I do though not have reference for it.

Hans

Re: Too narrowly defined: DIVISION SIGN COLON

2012-07-12 Thread Stephan Stiller



1. Michael Everson wrote:

Still it might be interesting to see the symbols-a4.pdf.
I have always wanted to see an associative array for The Comprehensive 
LaTeX Symbol List mapping symbols to sets of use cases, considering 
only standardized usage and perhaps only the literature that would be 
considered part of the curricula all grad students in some field would 
encounter. (Like, all the literature covering core math areas. I know, 
this will be fuzzy around the edges.)


Because I don't think the Simpsons characters belong into Unicode. And 
so many of the symbols from the packages covered by this symbol list 
seem to have been generated on a whim.


It might even be possible for someone to scour tex-files on the internet 
to get some real usage statistics.



2. Hans Aberg wrote:

TeX does not parse the formulas.
TeX associates classes with subformulas as well as with individual 
characters. (see Ch. 17 of The TeXbook) There are 8 such classes, and 
if TeX parses an expression incorrectly, one can change them on an 
ad-hoc basis. Sadly such things aren't taught well (like a lot about 
TeX/LaTeX that is needed for good typography), and that's why people 
mostly don't know about this and the underlying mechanics and why 
getting such things is a pain in practice, as one needs to look all over 
the place for answers.


Stephan

Re: Too narrowly defined: DIVISION SIGN COLON


On 7/12/2012 2:47 PM, Michael Everson wrote:

On 12 Jul 2012, at 22:20, Julian Bradfield wrote:


But wanting to do so would be crazy. My mu-nu ligature is, as far as I know, 
used only by me (and co-authors who let me do the typesetting), and so if 
Unicode has any sanity left, it would not encode it.

Is it in print?


My colleagues in the Edinburgh PEPA group did try to get their pet symbol 
encoded (a bowtie where the two triangles overlap somewhat rather than just 
touching), but were refused; although that symbol now appears in hundreds of 
papers by dozens of authors from all over the world.

If so, then it should be encoded.




Julian,

can you cite title or number of the original proposal document?

A./

Re: Too narrowly defined: DIVISION SIGN COLON


On 7/12/2012 3:10 PM, Julian Bradfield wrote:
If you read any introduction to TeX, it will explain how you use 
macros to provide a structured markup. If you were using that 
notation, then you would define a suitable macro, say 
\def\tetration#1#2{{}^{#2}{#1}} and write $\tetration{y}{x}$. This 
does not depend on any fancy Unicodery for its interpretation, and 
also allows you to define semantic content for the computer.


But that's like a private use character - fat chance of exchanging that 
with anybody not using the same software suite.


A./

Re: Too narrowly defined: DIVISION SIGN COLON


On 7/12/2012 2:47 PM, Michael Everson wrote:

On 12 Jul 2012, at 22:20, Julian Bradfield wrote:


But wanting to do so would be crazy. My mu-nu ligature is, as far as I know, 
used only by me (and co-authors who let me do the typesetting), and so if 
Unicode has any sanity left, it would not encode it.

Is it in print?


My colleagues in the Edinburgh PEPA group did try to get their pet symbol 
encoded (a bowtie where the two triangles overlap somewhat rather than just 
touching), but were refused; although that symbol now appears in hundreds of 
papers by dozens of authors from all over the world.

If so, then it should be encoded.




Can you cite title or number of the original proposal document?

A./

Re: Too narrowly defined: DIVISION SIGN COLON


On 11 Jul 2012, at 03:01, Leif Halvard Silli wrote:

 Hans Aberg, Tue, 10 Jul 2012 22:41:26 +0200:
 On 10 Jul 2012, at 21:30, Asmus Freytag wrote:
 On 7/10/2012 3:50 AM, Leif Halvard Silli wrote:
 Asmus Freytag, Mon, 09 Jul 2012 19:32:47 -0700:
 The European use (this is not limited to Scandinavia)
 Thanks. It seems to me that that this tradition is not without a link
 to the (also) European tradition of *not* using the DIVISION SIGN (÷)
 for division.
 
 Is it _ever_ used for division? I'm curious, right now I can't 
 recall ever having seen an example.
 
 The WP Obelus article says that it was used as a sign for division 
 in 1659, otherwise used for subtraction, continued in Norway, and 
 until recently, in Denmark.
 
 https://en.wikipedia.org/wiki/Obelus
 
 Thanks. Scandinavia's history indicates that if known in Denmark, 
 Norway and Finland, then it should be known on Iceland and in Sweden 
 too. 

I can't recall the obelus being used for anything math in Sweden, and Bonnier's 
encyclopedia from 1965, in its matemmatik article, says that : is used for 
division and / to denote fractions. I think it is the traditional use, before 
the days of computers.

Hans

Re: Too narrowly defined: DIVISION SIGN COLON

2012-07-11 Thread Escape Landsome

 U+00B7 MIDDLE DOT
 * also used to denote multiplication, for that usage 22C5 · DOT OPERATOR is
 preferred

 * also used in Catalan as a right-side diacritic added after a LATIN LETTER L.
 * also used in some languages as a syllabic or morphemic separation
 hyphen (distinct from the hyphen used to link compound words) for
 breaking words on margin boundaries.

* also used in Renaissance mathematical papers to denote what is the
decimal dot today (as in 3.14159)

Re: Too narrowly defined: DIVISION SIGN COLON

On 11 Jul 2012, at 02:05, Ken Whistler wrote:

 Incidentally, one of the reasons the set of symbols in the U+2200
 Mathematical Operators block got a somewhat different treatment than
 generic punctuation or other symbols or combining marks, when it comes
 to unification versus non-unification decisions back in the original
 draft charts in 1989 and 1990 had something to do with the intuition
 back then that having unambiguous encodings for the math operators
 would be important for machine processing of mathematical data
 (as in algebra systems).

The spacing in different in mathematics between a colon and the mathematical 
operator :, and they are distinguished in TeX. For example, $f\colon A 
\rightarrow B$ and $x = c:d$.

 It isn't so clear now, in retrospect, whether
 some of the disunifications were a good idea or not. But those
 decisions are what we have inherited in the standard now, for better
 or worse.

When using program like XeTeX or LuaTeX that can use Unicode input text files, 
it may be desirable to do it by means of different Unicode characters rather 
than TeX macros. So at least some of those distinctions may be important.

Hans

Re: Too narrowly defined: DIVISION SIGN COLON

On 11 Jul 2012, at 03:51, Khaled Hosny wrote:

 It can be handled at a different level; when one types 3:5 in a
 Unicode-complient TeX engine, what gets output to the output file is the
 ratio not the colon, and colon gets output with 3\colon{}5.

Actually, TeX does it wrongly relative Unicode: a colon : in the input file 
should expand TeX $\colon$, whereas ∶ RATIO U+2236 should expand to TeX $:$.

Hans

Re: Too narrowly defined: DIVISION SIGN COLON

2012-07-11 Thread Leif Halvard Silli

Hans Aberg, Wed, 11 Jul 2012 10:20:11 +0200:
 https://en.wikipedia.org/wiki/Obelus
 
 Thanks. Scandinavia's history indicates that if known in Denmark, 
 Norway and Finland, then it should be known on Iceland and in Sweden 
 too. 
 
 I can't recall the obelus being used for anything math in Sweden, and 
 Bonnier's encyclopedia from 1965, in its matemmatik article, says 
 that : is used for division and / to denote fractions. I think it 
 is the traditional use, before the days of computers.

I looked in the Swedish books I have, from around 1810 to 1950, about 
time reckoning ([fake Swedish alert:] kalenderstickor, 
söndagsbokstäver, påskdags-räkning etc), and I could not find the it, 
either ... So, we might belong to different traditions that way. ;-) If 
so, then all the more interesting why Finland have it ...

I know I have provided enough documentation now, but I just looked my 
copy of a classic Norwegian book from 1971 on time reckoning, calendar 
etc,[1] and he used both the – and the ÷ as minus, but predominantly 
the ÷, it seems.

[1] http://books.google.no/books/about/?id=kHgyQwAACAAJ
-- 
Leif Halvard Silli

Re: Too narrowly defined: DIVISION SIGN COLON

On 11 Jul 2012, at 12:15, Leif Halvard Silli wrote:

 Hans Aberg, Wed, 11 Jul 2012 10:20:11 +0200:
 https://en.wikipedia.org/wiki/Obelus
 
 Thanks. Scandinavia's history indicates that if known in Denmark, 
 Norway and Finland, then it should be known on Iceland and in Sweden 
 too. 
 
 I can't recall the obelus being used for anything math in Sweden, and 
 Bonnier's encyclopedia from 1965, in its matemmatik article, says 
 that : is used for division and / to denote fractions. I think it 
 is the traditional use, before the days of computers.
 
 I looked in the Swedish books I have, from around 1810 to 1950, about 
 time reckoning ([fake Swedish alert:] kalenderstickor, 
 söndagsbokstäver, påskdags-räkning etc), and I could not find the it, 
 either ... So, we might belong to different traditions that way. ;-) If 
 so, then all the more interesting why Finland have it …

Norway picked up the Danish writing system. Swedish perhaps was influenced by 
French in the past for political reasons; perhaps the Danish conventions come 
from Germany. I do not know about Finland.

Hans

Raised decimal dot (was: Re: Too narrowly defined: DIVISION SIGN COLON)

2012-07-11 Thread Karl Pentzlin

Am Dienstag, 10. Juli 2012 um 22:28 schrieb Asmus Freytag:

AF ... A nice argument can be made for encoding a raised decimal
AF dot (if it's not representable by any number of other raised dots 
AF already encoded). Clearly, in the days of lead typography, a
AF British style decimal dot would have been something that was a
AF distinct piece of lead from a period. ...

Is U+2E33 RAISED DOT suited for this?
According to the annotation in the standard, the glyph position [is]
intermediate between U+002E . and 00B7 · (i.e., ¼ cap height).
Can somebody point to examples?

- Karl

Re: Too narrowly defined: DIVISION SIGN COLON

2012-07-11 Thread Leif Halvard Silli

Leif Halvard Silli, Wed, 11 Jul 2012 03:01:53 +0200:
 Btw, the venerable Danish Salomonsens conversional encyclopedia, the 
 1924 edition, says, that subtraction, quote: is written a – b or a ÷ 
 b, where the – and the ÷ is called the minus sign. [7] So it sounds as 
 if it saw it as shapes of the very same character. And this also makes 
 sense when we consider that we historically apparently never used the ÷ 
 for division.

The same encyclopedia on Division says: [1]

]] If the dividend or the divisor is not both of the positive, one 
divided their numeric values and places a + or a ÷ in front of the 
quotient, depending on [ ... snip ...] [[

The striking thing here is that it talks about division and recommends 
÷ for signifying negative value without even discussing the use of ÷ as 
division signal or hint that there could be possibility for confusion. 
Which in turn hints that there were no danger for confusion ...

[1] http://runeberg.org/salmonsen/2/6/0251.html
-- 
Leif H Silli

Re: Too narrowly defined: DIVISION SIGN COLON

2012-07-11 Thread Khaled Hosny

On Wed, Jul 11, 2012 at 10:47:33AM +0200, Hans Aberg wrote:
 On 11 Jul 2012, at 03:51, Khaled Hosny wrote:
 
  It can be handled at a different level; when one types 3:5 in a
  Unicode-complient TeX engine, what gets output to the output file is the
  ratio not the colon, and colon gets output with 3\colon{}5.
 
 Actually, TeX does it wrongly relative Unicode: a colon : in the
 input file should expand TeX $\colon$, whereas ∶ RATIO U+2236 should
 expand to TeX $:$.

It is a kind of primitive input method, like using / for division slash
and * for asterisk operator, and ratio is more frequent in math than the
colon. (original TeX handled this by having different glyphs/glyph
classes in math than TeX, Unicode-compliant TeX engines map them to the
appropriate Unicode character).

Regards,
 Khaled

Re: Too narrowly defined: DIVISION SIGN COLON

On 11 Jul 2012, at 15:59, Khaled Hosny wrote:

 On Wed, Jul 11, 2012 at 10:47:33AM +0200, Hans Aberg wrote:
 On 11 Jul 2012, at 03:51, Khaled Hosny wrote:
 
 It can be handled at a different level; when one types 3:5 in a
 Unicode-complient TeX engine, what gets output to the output file is the
 ratio not the colon, and colon gets output with 3\colon{}5.
 
 Actually, TeX does it wrongly relative Unicode: a colon : in the
 input file should expand TeX $\colon$, whereas ∶ RATIO U+2236 should
 expand to TeX $:$.
 
 It is a kind of primitive input method, like using / for division slash
 and * for asterisk operator, and ratio is more frequent in math than the
 colon. (original TeX handled this by having different glyphs/glyph
 classes in math than TeX, Unicode-compliant TeX engines map them to the
 appropriate Unicode character).

There are a number of other incompatibilities between original TeX and Unicode:

For example, ASCII letters are in TeX math mode typeset in italics, but Unicode 
has a mathematical italics style, so ASCII letters should be typeset upright in 
a strict Unicode mode. And similar for Greek letters, I gather.

If I try the code below in lualatex, then the 푩 and the 퐁 both come out typeset 
upright.

Also, in the code there is an example where spacing produces a semantic 
difference: {A: B} is the set of all A satisfying the predicate B, whereas {A : 
B} is the set of the single element A : B. (It is more common to use | 
nowadays in the first case, but it is also used as an operator.)

Hans



\documentclass{article}

\usepackage{amsmath}

\usepackage{fontspec}
\usepackage{unicode-math}

\defaultfontfeatures{Ligatures=TeX}

\setmainfont{XITS}
\setmathfont{XITS Math}

\begin{document}

$f\colon A → 푩, 퐁$ and $x = c:d:e$

$f∶ A → B$ and $x = c:d∶e$

$\{A\colon P\}$ and $\{A:P\}$.

\end{document}

Re: Too narrowly defined: DIVISION SIGN COLON

2012-07-11 Thread Khaled Hosny

On Wed, Jul 11, 2012 at 04:20:26PM +0200, Hans Aberg wrote:
 On 11 Jul 2012, at 15:59, Khaled Hosny wrote:
 
  On Wed, Jul 11, 2012 at 10:47:33AM +0200, Hans Aberg wrote:
  On 11 Jul 2012, at 03:51, Khaled Hosny wrote:
  
  It can be handled at a different level; when one types 3:5 in a
  Unicode-complient TeX engine, what gets output to the output file is the
  ratio not the colon, and colon gets output with 3\colon{}5.
  
  Actually, TeX does it wrongly relative Unicode: a colon : in the
  input file should expand TeX $\colon$, whereas ∶ RATIO U+2236 should
  expand to TeX $:$.
  
  It is a kind of primitive input method, like using / for division slash
  and * for asterisk operator, and ratio is more frequent in math than the
  colon. (original TeX handled this by having different glyphs/glyph
  classes in math than TeX, Unicode-compliant TeX engines map them to the
  appropriate Unicode character).
 
 There are a number of other incompatibilities between original TeX and
 Unicode:
 
 For example, ASCII letters are in TeX math mode typeset in italics,
 but Unicode has a mathematical italics style, so ASCII letters should
 be typeset upright in a strict Unicode mode. And similar for Greek
 letters, I gather.
 
 If I try the code below in lualatex, then the 푩 and the 퐁 both come
 out typeset upright.

There is a “literal” mode in unicode-math package just for that, check
its manual for more details.

 Also, in the code there is an example where spacing produces a
 semantic difference: {A: B} is the set of all A satisfying the
 predicate B, whereas {A : B} is the set of the single element A : B.
 (It is more common to use | nowadays in the first case, but it is
 also used as an operator.)

There is also an option to control colon vs. ratio behaviour, but this
is getting off-topic IMO.

Regards,
 Khaled

Re: Too narrowly defined: DIVISION SIGN COLON

2012-07-11 Thread Julian Bradfield

On 2012-07-11, Hans Aberg haber...@telia.com wrote:
 There are a number of other incompatibilities between original TeX and 
 Unicode:

 For example, ASCII letters are in TeX math mode typeset in italics, but 
 Unicode has a mathematical italics style, so ASCII letters should be typeset 
 upright in a strict Unicode mode. And similar for Greek letters, I gather.

Unicode is about plain text. TeX is about fine typesetting.
There's no reason why TeX should typeset ASCII as upright, any more
than it should typeset \begin{section} as that literal string! The
use of ASCII characters in math mode is simply an input convention, to
indicate the desired output of italic letters in a style appropriate
for single-letter mathematical variables.
The use of other Unicode characters in TeX input files is also simply
an input convention; how they get typeset depends on many other things
than what they look like in the code charts.

-- 
The University of Edinburgh is a charitable body, registered in
Scotland, with registration number SC005336.

Re: Too narrowly defined: DIVISION SIGN COLON

On 11 Jul 2012, at 16:33, Khaled Hosny wrote:

 If I try the code below in lualatex, then the 푩 and the 퐁 both come
 out typeset upright.
 
 There is a “literal” mode in unicode-math package just for that, check
 its manual for more details.

As for the ISO standards mentioned in section 5.2 Bold style, I think they 
call for the use of sans-serif fonts. In pure math, one uses serif fonts, also 
for tensors, which do not have any fixed notation. Also, it is traditional to 
typeset variables in italics and constants in upright, but this has not been 
strictly adhered to, perhaps due to the lack of fonts. For example, it is 
possible to make difference between the imaginary unit i, a constant, and an 
index i, a variable, but it is rare to see the former in upright style, 
sometimes leading to funny formulas where they are mixed.

Unicode adds all variations: serif/sans serif, upright/italics. In principle, 
one could use all styles side-by-side indicating semantically different objects.

Hans

Re: Too narrowly defined: DIVISION SIGN COLON

On 11 Jul 2012, at 18:20, Julian Bradfield wrote:

 On 2012-07-11, Hans Aberg haber...@telia.com wrote:
 There are a number of other incompatibilities between original TeX and 
 Unicode:
 
 For example, ASCII letters are in TeX math mode typeset in italics, but 
 Unicode has a mathematical italics style, so ASCII letters should be typeset 
 upright in a strict Unicode mode. And similar for Greek letters, I gather.
 
 Unicode is about plain text. TeX is about fine typesetting.
 There's no reason why TeX should typeset ASCII as upright, any more
 than it should typeset \begin{section} as that literal string! The
 use of ASCII characters in math mode is simply an input convention, to
 indicate the desired output of italic letters in a style appropriate
 for single-letter mathematical variables.
 The use of other Unicode characters in TeX input files is also simply
 an input convention; how they get typeset depends on many other things
 than what they look like in the code charts.

Unicode has added all the characters from TeX plus some, making it possible to 
use characters in the input file where TeX is forced to use ASCII. This though 
changes the paradigm, and it is a question of which paradigm one wants to 
adhere to.

Hans

Re: Too narrowly defined: DIVISION SIGN COLON

2012-07-11 Thread Jukka K. Korpela


2012-07-11 19:33, Hans Aberg wrote:


As for the ISO standards mentioned in section 5.2 Bold style,


I’m sorry, I’ve lost the context: section 5.2 of what?


I think they call for the use of sans-serif fonts.


The ISO standard on mathematical notations, ISO 8-2, is very vague 
about fonts: “It is customary to use different sorts of letters for 
different sorts of entities. This makes formulas more readable and helps
in setting up an appropriate context. There are no strict rules for the 
use of letter fonts which should, however, be explained if necessary.” 
(clause 3)


The standard itself uses a sans-serif font throughout, as ISO standards 
in general. This is unfortunate for many reason. Sans-serif fonts are 
generally unsuitable for mathematical texts. Moreover, if your overall 
font is sans-serif, some essential distinctions are lost, since tensors 
and symbols for dimensions are conventionally rendered in sans-serif 
font as opposite to the tradition of using serif fonts for mathematics. 
This is one of the reasons for “mathematical sans-serif” characters in 
Unicode.


 In pure math, one uses serif fonts, also for tensors, which do not 
have any fixed notation.


Pure math, applied math, and physics partly use conflicting conventions 
for some notations. Standards are supposed to remove unnecessary and 
disturbing differences, at least in the long run. And ISO 8-2 says: 
“Two arrows above the letter symbol can be used instead of bold face 
sans serif type to indicate a tensor of the second order.” (2-17.19) 
This implies that the normal, basic notation uses bold sans-serif for 
tensors.


 Also, it is traditional to typeset variables in italics and constants 
in upright,


There is considerable variation here. By ISO 8-2, *mathematical* 
constants such as i, e, π, and γ are denoted by upright symbols, whereas 
*physical* constants such as c (speed of light in vacuum) are treated as 
denoting *quantities* and therefore italicized. It is however very 
common in mathematics (but not that much in physics) to italicize 
mathematical constants



but this has not been strictly adhered to, perhaps due to the lack of fonts.


I think the diversity is mostly due to traditions. Mathematicians tend 
to be very conservative in notational issues.



Unicode adds all variations: serif/sans serif, upright/italics.
In principle, one could use all styles side-by-side indicating semantically 
different objects.


Yes, you could, but I think it’s not *normal* to make the distinctions 
at the character level. Rather, higher-level protocols are used to 
indicate italics, bolding, and font family. One obvious reason is that 
it is rather clumsy to *type* the mathematical italic, mathematical 
sans-serif, etc., characters and usually very easy to use font or style 
settings, markup, or style sheets for italics etc.


I was surprised at realizing that MS Word 2007 and newer, when 
processing formulas, internally converts normal characters to 
mathematical italic and relative. For example, in formula mode, when you 
type “x”, Word by default changes it to mathematical italic x. It does 
*not* used a normal “x” of the font it uses in formulas (Cambria 
Math)—that font lacks italic, and if you “italicize” it, you get fake 
italic, algorithmically slanted normal letter, which is very different 
from mathematical italic letters of the font.


It’s interesting to see such usage—it’s probably the most common use of 
non-BMP characters that people encounter, even thought we are usually 
ignorant of what’s really happening here, and it *looks* like play with 
fonts only.


Yucca

Re: Too narrowly defined: DIVISION SIGN COLON

2012-07-11 Thread Marion Gunn


On 11/07/2012 18:30, Jukka K. Korpela wrote:
... For example, in formula mode, when you type “x”, Word by default 
changes it to mathematical italic x. It does *not* used a normal “x” 
of the font it uses in formulas (Cambria Math)—that font lacks italic, 
and if you “italicize” it, you get fake italic, algorithmically 
slanted normal letter, which is very different from mathematical 
italic letters of the font.



That is amusing. I spent a lot of time trying to find math symbol x 
when preparing a document in MSWord for publication, before discovering 
I didn't have to search for that at all!

:-)
mg




It’s interesting to see such usage—it’s probably the most common use 
of non-BMP characters that people encounter, even thought we are 
usually ignorant of what’s really happening here, and it *looks* like 
play with fonts only.


Yucca



--
Marion Gunn * eGteo (Estab.1991)
27 Páirc an Fhéithlinn, Baile an
Bhóthair, An Charraig Dhubh,
Co. Átha Cliath, Éire/Ireland.
* mg...@egt.ie * eam...@egt.ie *

Re: Too narrowly defined: DIVISION SIGN COLON

2012-07-11 Thread Eric Muller


On 7/11/2012 9:20 AM, Julian Bradfield wrote:
Unicode is about plain text. TeX is about fine typesetting. 


Too narrowly defined: Unicode.

I think Unicode is not just for plain text, but rather concerns itself 
with only the lower layer of /any /text system.


When it's plain text, Unicode has the burden of solving all the 
problems. When it's a richer system, there is the issue of cooperation 
between the layers, a situation that Unicode cannot ignore.


Eric.

Re: Too narrowly defined: DIVISION SIGN COLON

On 11 Jul 2012, at 19:30, Jukka K. Korpela wrote:

2012-07-11 19:33, Hans Aberg wrote:

There is a “literal” mode in unicode-math package just for that, check
its manual for more details.

As for the ISO standards mentioned in section 5.2 Bold style,

I’m sorry, I’ve lost the context: section 5.2 of what?

Yes, you snipped it; I have put it back.

I think they call for the use of sans-serif fonts.

The ISO standard on mathematical notations, ISO 8-2, is very vague about
fonts: “It is customary to use different sorts of letters for different sorts
of entities. This makes formulas more readable and helps
in setting up an appropriate context. There are no strict rules for the use
of letter fonts which should, however, be explained if necessary.” (clause 3)

There was mentioned a standard for tensors for technical use specifically, but
I do not recall which it was.

The standard itself uses a sans-serif font throughout, as ISO standards in
general. This is unfortunate for many reason. Sans-serif fonts are generally
unsuitable for mathematical texts. Moreover, if your overall font is
sans-serif, some essential distinctions are lost, since tensors and symbols
for dimensions are conventionally rendered in sans-serif font as opposite to
the tradition of using serif fonts for mathematics. This is one of the
reasons for “mathematical sans-serif” characters in Unicode.

Originally, it was probably just different styles I think, as opposed to
different (mathematical) styles, but somehow sans-serif for tensors became
popular, and that was part of the motivation for adding mathematical sans-serif
styles to Unicode.

A similar thing happened with the mono-space characters: in computing, style
does not change semantics, in fact, some older books I have do not use
monospace for computer code. But now that they added to Unicode, they could be
used to leave the ASCII subset for serif letters.

In pure math, one uses serif fonts, also for tensors, which do not have any
fixed notation.

Pure math, applied math, and physics partly use conflicting conventions for
some notations.

Right. And inconsistencies perhaps have increased, since professional
typesetters do not do that job anymore.

Standards are supposed to remove unnecessary and disturbing differences, at
least in the long run. And ISO 8-2 says: “Two arrows above the letter
symbol can be used instead of bold face sans serif type to indicate a tensor
of the second order.” (2-17.19) This implies that the normal, basic notation
uses bold sans-serif for tensors.

Those are originally styles used in the absence of fonts, including handwriting.

Also, it is traditional to typeset variables in italics and constants in
upright,

There is considerable variation here. By ISO 8-2, *mathematical*
constants such as i, e, π, and γ are denoted by upright symbols, whereas
*physical* constants such as c (speed of light in vacuum) are treated as
denoting *quantities* and therefore italicized. It is however very common in
mathematics (but not that much in physics) to italicize mathematical constants

In the past, it was uncommon to have different styles for Greek, so you would
have to take whatever available. Constants like i, e, whatever would probably
end up in italic, with upright reserved for names like sin.

But it is now possible to distinguish between constants and variables
systematically, now that the Unicode mathematical styles are available.

but this has not been strictly adhered to, perhaps due to the lack of fonts.

I think the diversity is mostly due to traditions. Mathematicians tend to be
very conservative in notational issues.

In the days before electronic typesetting, lack of suitable fonts is said to
have been a problem due to the cost of having those fonts available. One might
use a typewriter, with even a higher limited number of symbols, and do mark up
by hand. Here is one example:

http://books.google.se/books?id=KCOuGztKVgcCprintsec=frontcoverdq=alonzo+churchhl=ensa=Xei=Xcb9T-34MrL54QSZqJD5Bgredir_esc=y#v=onepageq=alonzo%20churchf=false

Unicode adds all variations: serif/sans serif, upright/italics.
In principle, one could use all styles side-by-side indicating semantically
different objects.

Yes, you could, but I think it’s not *normal* to make the distinctions at the
character level. Rather, higher-level protocols are used to indicate italics,
bolding, and font family. One obvious reason is that it is rather clumsy to
*type* the mathematical italic, mathematical sans-serif, etc., characters and
usually very easy to use font or style settings, markup, or style sheets for
italics etc.

Yes, that is another problem: the lack of efficient input methods. But Unicode
now supports those styles and variations at the character level, so they could
be used.

I was surprised at realizing that MS Word 2007 and newer, when processing
formulas, internally

Re: Too narrowly defined: DIVISION SIGN COLON

2012-07-11 Thread Asmus Freytag


On 7/11/2012 11:02 AM, Eric Muller wrote:

On 7/11/2012 9:20 AM, Julian Bradfield wrote:
Unicode is about plain text. TeX is about fine typesetting. 


Too narrowly defined: Unicode.

I think Unicode is not just for plain text, but rather concerns itself 
with only the lower layer of /any /text system.


When it's plain text, Unicode has the burden of solving all the 
problems. When it's a richer system, there is the issue of cooperation 
between the layers, a situation that Unicode cannot ignore.


Eric.


Nicely put, Eric!

A./

Re: Too narrowly defined: DIVISION SIGN COLON

2012-07-10 Thread Jukka K. Korpela


2012-07-10 5:32, Asmus Freytag wrote:


There are many characters that are used in professional mathematical
typesetting (division slash being one of them) that need to be narrowly
distinguished from other, roughly similar characters.


Typographic differences can be made at glyph selection level, too, or 
even in font design and choice of font. Typesetting systems like TeX and 
derivatives have been very successful along such lines.



Such narrowly defined characters are not aimed at the general user, and
it's totally irrelevant whether or not such a character ever becomes
popular.


Popularity is relative to a population. When I wrote that “narrow 
semantics does not make characters popular”, relating to the case of 
DIVISION SLASH, I referred to popularity among people who could 
conceivably have use for the characters. I don’t think there’s much 
actual use of DIVISION SLASH in the wild. And this was about a case 
where the distinction is not only semantic (actually the Unicode 
standard does not describe the semantic side of the matter except 
implicitly via things like Unicode name and General Category of the 
character) but also has, or may have, direct impact on rendering.



Very early in the design cycle for Unicode there
was a request for encoding of a decimal period, in distinction to a full
stop. The problem here is that there is no visual distinction


This is more or less a vicious circle, and the starting point isn’t even 
true. In British usage, the decimal point is often a somewhat raised 
dot, above the baseline. But even if we assume that no distinction *had 
been made* before the decision, the decision itself implied that no 
distinction *can be made* by choice of character.


If a different decision had been made, people could choose to use a 
decimal point character, or they could keep using just the ambiguous 
FULL STOP character. Font designers could make them identical, or they 
could make them different. But most probably, most people would not even 
be aware of the matter: they would keep pressing the keyboard key 
labeled with “.” – that is, the decimal point character would not have 
much popularity. In British typesetting, people would probably still use 
whatever methods they now use to produce raised dots.



Unicode has relatively consistently refused to duplicate encodings in
such circumstances, because the point about Unicode is not that one
should be able to encode information about the intent that goes beyond
what can be made visible by rendering the text. Instead, the point about
Unicode is to provide a way to unambiguously define enough of the text
so that it becomes legible. How legible text is then understood is
another issue.


That’s a nice compact description of the principle, but perhaps the real 
reasons also include the desire to avoid endless debates over 
“semantics”. Some semantic differences, like the use of a character as a 
punctuation symbol vs. as a mathematical symbol, are relatively clear. 
Most semantics differences that can be made are not that clear at all.



Because of that, there was never any discussion whether the ! would have
to be re-encoded as factorial. It was not.


This implies that if anyone thinks that the factorial symbol should look 
different from a normal exclamation mark, to avoid ambiguity (as in the 
sentence “The result is n!”), he cannot do that at the character level.


A large number of mathematical and other symbols have originated as 
other characters used for special purposes, then styled to have 
distinctive shapes, later identified as separate symbols. For example, 
N-ARY SUMMATION ∑ is now mostly visually different from GREEK CAPITAL 
LETTER SIGMA Σ, though it was originally just the Greek letter used in a 
specific meaning and context.


A principle that refuses to “re-encode” characters for semantic 
distinctions seems to put a stop on such development. But of course new 
characters are still being developed from old characters for various 
purposes and can be encoded. They just need to have some visual identity 
different from the old characters from the very start, to have a chance 
of getting encoded.



The proper thing to do would be to add these usages to the list of
examples of known contextually defined usages of punctuation characters,
they are common enough that it's worth pointing them out in order to
overcome a bit of the inherent bias from Anglo-Saxon usage.


So what would be needed for this? I previously suggested annotations like

: also used to denote division

and

÷ also used to denote subtraction

But perhaps the former should be a little longer:

:  also used to denote division and ratio

(especially since the use for ratio is more official and probably more 
common).


Yucca

Re: Too narrowly defined: DIVISION SIGN COLON

2012-07-10 Thread Joó Ádám

 A very quick browse of Wikipedia showed me that the
 colon as division sign is common in Ukraine, Russia, Sweden and Germany
 too. (Thus, English Wikipedia fittingly acknowledges that 'In some
 non-English-speaking cultures, a divided by b is written a : b.' [9])

In Hungary it is the notation of inline division taught in elementary
school, horizontal bar employed for built-up fractions. In upper
classes and in everyday use solidus seems to be much more common.

Á

Re: Too narrowly defined: DIVISION SIGN COLON

Asmus Freytag, Mon, 09 Jul 2012 19:32:47 -0700:
 The European use (this is not limited to Scandinavia)

Thanks. It seems to me that that this tradition is not without a link 
to the (also) European tradition of *not* using the DIVISION SIGN (÷) 
for division.

 The proper thing to do would be to add these usages to the list of 
 examples of known contextually defined usages of punctuation 
 characters, they are common enough that it's worth pointing them out 
 in order to overcome a bit of the inherent bias from Anglo-Saxon 
 usage.

(Did you intend to denote DIVISION SIGN as a punctuation character?)

Where do I find the (existing) examples? In the PDF version of the 
spec? Or, also, in the texts files that look-up tools uses? (I guess I 
think about annotation.) For instance, would be possible, in the the 
NamesList, or some other field that look-up tools uses, to get a link 
from e.g. COLON to DIVISION SIGN, and vice versa? And similar, from 
MINUS TO DIVISION SIGN and vice versa?

My candidate characters, this round, are:

 DIVISION SIGN (÷) as minus sign.
 COLON (:) as division sign.
MIDDLE DOT (·) as multiplication symbol.

What's next? Would some formal action be needed?
-- 
Leif Halvard Silli

Re: Too narrowly defined: DIVISION SIGN COLON

2012/7/10 Leif Halvard Silli xn--mlform-...@xn--mlform-iua.no:
 Asmus Freytag, Mon, 09 Jul 2012 19:32:47 -0700:
 The European use (this is not limited to Scandinavia)

 Thanks. It seems to me that that this tradition is not without a link
 to the (also) European tradition of *not* using the DIVISION SIGN (÷)
 for division.

Why European ? I never heard before this discussion that the DIVISION
SIGN (÷) would be used to mean a substraction. And I leave in Europe.
This sign was even the first one I learned for the division at school
when I was a child, long before the slash (/), and later the colon (:)
essentially for noting scale ratios on maps.

Re: Too narrowly defined: DIVISION SIGN COLON

2012-07-10 Thread Andrew West

On 10 July 2012 11:50, Leif Halvard Silli
xn--mlform-...@xn--mlform-iua.no wrote:

 My candidate characters, this round, are:

  DIVISION SIGN (÷) as minus sign.
  COLON (:) as division sign.
 MIDDLE DOT (·) as multiplication symbol.

The last one is already encoded as U+22C5 DOT OPERATOR.

 What's next? Would some formal action be needed?

Yes. If you really want to propose them then you must submit a
proposal form to Unicode and/or WG2:

http://www.unicode.org/pending/proposals.html

But I very much doubt that the committees would accept such characters
for encoding.

Andrew

Re: Too narrowly defined: DIVISION SIGN COLON

2012-07-10 Thread Jukka K. Korpela


2012-07-10 15:33, Andrew West wrote:


On 10 July 2012 11:50, Leif Halvard Silli
xn--mlform-...@xn--mlform-iua.no wrote:


My candidate characters, this round, are:

  DIVISION SIGN (÷) as minus sign.
  COLON (:) as division sign.
 MIDDLE DOT (·) as multiplication symbol.


The last one is already encoded as U+22C5 DOT OPERATOR.


What's next? Would some formal action be needed?


Yes. If you really want to propose them then you must submit a
proposal form to Unicode and/or WG2:

http://www.unicode.org/pending/proposals.html


I don’t think Leif meant proposing new characters. Instead, I suppose he 
meant adding annotations to existing characters, changing the text of 
the standards (probably in the code charts, though notes about uses of 
individual characters also appear scattered around the chapters of the 
standard, too).


Yucca

Re: Too narrowly defined: DIVISION SIGN COLON

2012-07-10 Thread Andrew West

On 10 July 2012 13:52, Jukka K. Korpela jkorp...@cs.tut.fi wrote:

 Yes. If you really want to propose them then you must submit a
 proposal form to Unicode and/or WG2:

 http://www.unicode.org/pending/proposals.html

 I don’t think Leif meant proposing new characters. Instead, I suppose he
 meant adding annotations to existing characters, changing the text of the
 standards (probably in the code charts, though notes about uses of
 individual characters also appear scattered around the chapters of the
 standard, too).

OK, in that case he needs to file a report at:

http://www.unicode.org/reporting.html

Andrew

Re: Too narrowly defined: DIVISION SIGN COLON

Philippe Verdy, Tue, 10 Jul 2012 13:50:03 +0200:
 2012/7/10 Leif Halvard Silli:
 Asmus Freytag, Mon, 09 Jul 2012 19:32:47 -0700:
 The European use (this is not limited to Scandinavia)
 
 Thanks. It seems to me that that this tradition is not without a link
 to the (also) European tradition of *not* using the DIVISION SIGN (÷)
 for division.
 
 Why European ?

We have 3 accounts which say that is European: I, Jukka and Asmus. It 
might be spread wider ... But perhaps your point was that it is more 
narrow? ;-)

 I never heard before this discussion that the DIVISION
 SIGN (÷) would be used to mean a substraction.

I was about to say that the ÷ is only used as to signify an 
independent, negative number. E.g. on a thermometer and other places 
where the negative number stands on its own. For instance, in PR 
material (÷50%!), then that is how it is used. But then I looked up a 
small book on the almanac from 1920,[1] written by a head teacher in 
mathematics, and he uses ÷ everywhere. E.g. from page 16: 26 ÷ 12 = 14.

Btw, I also checked with the mathematical works of Niels Henrik Abel, 
from first half of the 19th century. And he did not seem to use the ÷ 
symbol at all. Not as subtraction symbol, not as negative number symbol 
and not as division symbol. You can check his works yourself - they are 
mostly in French.[2]

 And I leave in Europe.
 This sign was even the first one I learned for the division at school
 when I was a child, long before the slash (/), and later the colon (:)
 essentially for noting scale ratios on maps.

I have no recollection of when I learned the DIVISION SIGN (÷) as 
division sign. But I have a recollection of asking someone about what 
that sign meant when used on a calculator ... Today I am probably more 
than 4 times as old as when I asked that question - and it is all a bit 
in the haze ... But I am quite certain that I learned its meaning as 
subtraction symbol before I learned about its meaning as DIVISION 
symbol. (I started to attend school in the mid 1970-ties.) The only 
thing I am 100% certain about, regardless of what meaning we learned, 
is that we did not learn to write the (handwritten) ÷ symbol.

[1] http://books.google.no/books?id=HpoAcgAACAAJdq
[2] http://www.abelprize.no/c54178/seksjon/vis.html?tid=54179
-- 
Leif Halvard Silli

Re: Too narrowly defined: DIVISION SIGN COLON

Jukka K. Korpela, Tue, 10 Jul 2012 15:52:27 +0300:
 2012-07-10 15:33, Andrew West wrote:
 
 On 10 July 2012 11:50, Leif Halvard Silli wrote:
 
 My candidate characters, this round, are:
 
   DIVISION SIGN (÷) as minus sign.
   COLON (:) as division sign.
  MIDDLE DOT (·) as multiplication symbol.
 
 The last one is already encoded as U+22C5 DOT OPERATOR.
 
 What's next? Would some formal action be needed?
 
 Yes. If you really want to propose them then you must submit a
 proposal form to Unicode and/or WG2:
 
 http://www.unicode.org/pending/proposals.html
 
 I don’t think Leif meant proposing new characters. Instead, I suppose 
 he meant adding annotations to existing characters, changing the text 
 of the standards (probably in the code charts, though notes about 
 uses of individual characters also appear scattered around the 
 chapters of the standard, too).

Correct. That was what I meant, above.
-- 
Leif H Silli

Re: Too narrowly defined: DIVISION SIGN COLON

2012-07-10 Thread Christoph Päper

Leif Halvard Silli:

  * that the DIVISION SIGN in the (human) mathematical notation of
at least one language (Norwegian) functions as a stylistically
distinct MINUS sign.

Ain’t that a stylistic, glyphic (i.e. font-dependent) variant of ‘⁒’ U+2052 
Commercial Minus Sign, not a special use of ‘÷’ U+00F7 Division Sign?

Re: Too narrowly defined: DIVISION SIGN COLON


On 7/10/2012 3:50 AM, Leif Halvard Silli wrote:

Asmus Freytag, Mon, 09 Jul 2012 19:32:47 -0700:

The European use (this is not limited to Scandinavia)

Thanks. It seems to me that that this tradition is not without a link
to the (also) European tradition of *not* using the DIVISION SIGN (÷)
for division.


Is it _ever_ used for division? I'm curious, right now I can't recall 
ever having seen an example.



The proper thing to do would be to add these usages to the list of
examples of known contextually defined usages of punctuation
characters, they are common enough that it's worth pointing them out
in order to overcome a bit of the inherent bias from Anglo-Saxon
usage.

(Did you intend to denote DIVISION SIGN as a punctuation character?)


It's a punctuation-like symbol. Let's leave it at that.

When it comes to rigorous division between these two classifications, 
I'm uncomfortable because those depend on usage - and this thread is 
another reminder that we (as maintainers of the standard) do not know 
enough about actual usage to make classifications that are correct in 
every instance


Where do I find the (existing) examples? In the PDF version of the
spec? Or, also, in the texts files that look-up tools uses? (I guess I
think about annotation.) For instance, would be possible, in the the
NamesList, or some other field that look-up tools uses, to get a link
from e.g. COLON to DIVISION SIGN, and vice versa? And similar, from
MINUS TO DIVISION SIGN and vice versa?


I would be in favor of extending the discussion of this topic in the 
text of the chapters on punctuation and symbols. Cross references are a 
bit of a blunt tool because they carry no explanation (they simply say: 
look here, not why the other character might be what you want).




My candidate characters, this round, are:

  DIVISION SIGN (÷) as minus sign.
  COLON (:) as division sign.
 MIDDLE DOT (·) as multiplication symbol.

What's next? Would some formal action be needed?


Now, about colon being used as division sign. Are you sure it's COLON 
that is used there, or is it (or should it be) U+2236 RATIO instead? I 
would think the latter is more likely the intended character with U+003C 
COLON merely being used as a fallback (RATIO is not on any keyboard).


The same question would apply for U+00B7 MIDDLE DOT. Even if it's in 
some data, is it there because it was the preferred character, or is it 
merely a fallback for U+2219 BULLET OPERATOR?


I would not be surprised to find out that these characters share some of 
the fate of HYPHEN-MINUS, that is, back during the time of 7 or 8-bit 
character standards, it was just easier to use the fallback. (And it 
still is, to some degree, because of the limitations of the basic but 
widely familiar keyboard layouts).


A./

Re: Too narrowly defined: DIVISION SIGN COLON


On 7/10/2012 4:50 AM, Philippe Verdy wrote:

2012/7/10 Leif Halvard Silli xn--mlform-...@xn--mlform-iua.no:

Asmus Freytag, Mon, 09 Jul 2012 19:32:47 -0700:

The European use (this is not limited to Scandinavia)

Thanks. It seems to me that that this tradition is not without a link
to the (also) European tradition of *not* using the DIVISION SIGN (÷)
for division.

Why European ? I never heard before this discussion that the DIVISION
SIGN (÷) would be used to mean a substraction. And I leave in Europe.
This sign was even the first one I learned for the division at school
when I was a child, long before the slash (/), and later the colon (:)
essentially for noting scale ratios on maps.

There's European and European.  If something is used in several European 
countries (perhaps not
even exclusively) it can be European in contrast to usage elsewhere in 
the world, without having

to be a usage that either uniform or universal across Europe.

But thanks for answering my earlier question.

I recall, with certainty, having seen the : in the context of 
elementary instruction in arithmetic,
as in 4 : 2 = ?, but am no longer positive about seeing ÷ in the same 
context. I'm glad the name
for this charatcer is not a case of yet another codified myth like the 
CARON


The use of this symbol on maps, to denote a scale, or ratio, is really 
something for which
U+2236 RATIO was encoded, with COLON just a popular fallback. Or do the 
mathematicians
make a systematic disctinction between RATIO and COLON (when used as 
mathematical operators).


A./

Re: Too narrowly defined: DIVISION SIGN COLON


On 7/10/2012 4:57 AM, Jukka K. Korpela wrote:

2012-07-10 13:50, Leif Halvard Silli wrote:


Asmus Freytag, Mon, 09 Jul 2012 19:32:47 -0700:

[…]

The proper thing to do would be to add these usages to the list of
examples of known contextually defined usages of punctuation
characters, they are common enough that it's worth pointing them out
in order to overcome a bit of the inherent bias from Anglo-Saxon
usage.

[…]

Where do I find the (existing) examples? In the PDF version of the
spec?


I’m not sure what Asmus meant, but I have thought that we are 
primarily discussing the annotations in the code charts, such as

http://unicode.org/charts/PDF/U0080.pdf
Information extracted from those charts is also available, perhaps in 
more useful ways, e.g. in the UniBook Character Browser, the BabelPad 
editor, and the Fileformat.info website (though they are not always 
up-to-date and they are not normative sources of information).


The MIDDLE dot has cross references there to DOT OPERATOR and BULLET and 
U+003A COLON points to RATIO





For instance, would be possible, in the the
NamesList, or some other field that look-up tools uses, to get a link
from e.g. COLON to DIVISION SIGN, and vice versa?


No, I don’t think that’s possible. But the code charts are what people 
use, or should use, so they are suitable for the purpose, even though 
they don’t use hyperlinks but just verbal references. (Hyperlinks are 
possible in PDF format, too, of course, but setting them up can be a 
major effort.)



My candidate characters, this round, are:

  DIVISION SIGN (÷) as minus sign.
  COLON (:) as division sign.
 MIDDLE DOT (·) as multiplication symbol.


Well, MIDDLE DOT is relatively often used as multiplication symbol, so 
it might be notified, but according to ISO 8-2, the correct 
dot-like multiplication symbol is DOT OPERATOR. There’s a possibility 
of creating misunderstandings if MIDDLE DOT is explicitly mentioned as 
a multiplication symbol. Such usage is indirectly referred to, or at 
least alluded to, by the cross-reference (of type “see also”) to 22C5 
DOT OPERATOR in the chart.


DOT OPERATOR and RATIO could use annotations identifying themselves as 
the non-fallback versions of these symbols.
Used in preference to U+ as character denoting operation  
would be a possible template.


00F7 DIVISION SIGN could usefully be annotated as: also used as an 
alternate, more visually distinct MINUS SIGN in some contexts with or 
without cross reference to U+2212 MINUS SIGN (and U+2052 COMMERCIAL 
MINUS SIGN could usefully get an reference to DIVISION SIGN)


A./

Re: Too narrowly defined: DIVISION SIGN COLON


On 7/10/2012 5:33 AM, Andrew West wrote:

On 10 July 2012 11:50, Leif Halvard Silli
xn--mlform-...@xn--mlform-iua.no wrote:

My candidate characters, this round, are:

  DIVISION SIGN (÷) as minus sign.
  COLON (:) as division sign.
 MIDDLE DOT (·) as multiplication symbol.

The last one is already encoded as U+22C5 DOT OPERATOR.


What's next? Would some formal action be needed?

Yes. If you really want to propose them then you must submit a
proposal form to Unicode and/or WG2:

http://www.unicode.org/pending/proposals.html

But I very much doubt that the committees would accept such characters
for encoding.



Encoding of new characters in not required to address the issue.
A./

Re: Too narrowly defined: DIVISION SIGN COLON


On 7/10/2012 11:25 AM, Christoph Päper wrote:

Leif Halvard Silli:


  * that the DIVISION SIGN in the (human) mathematical notation of
at least one language (Norwegian) functions as a stylistically
distinct MINUS sign.

Ain’t that a stylistic, glyphic (i.e. font-dependent) variant of ‘⁒’ U+2052 
Commercial Minus Sign, not a special use of ‘÷’ U+00F7 Division Sign?



No it ain't, ah, isn't.

Or, put it this way, how do you decide this question?
If you go back in time to before Unicode, all you have is the marks left 
in ink on a page.  If you find works that have ÷ as a minus sign and 
other works that have ÷ as a division symbol, how do you assert that 
these are different characters?


That seems nearly impossible.
If, instead, you magically had access to a comprehensive set of type 
catalogs of the time and found out that font showings listed either ÷ or 
⁒ but never both, then you might have an argument that these really 
were, at that time, considered glyph variants of each other. However, 
that still leaves you with the puzzling issue of how to accommodate the 
usage as division sign, without running afoul of arbitrary font-style 
variations.


As it happens, no such evidence has been brought forward, and with the 
encoding of U+2052 in Unicode 3.2, the encoding model is such that each 
of the two shapes correspond to separate characters.


A./

Re: Too narrowly defined: DIVISION SIGN COLON


On 7/9/2012 11:51 PM, Joó Ádám wrote:

A very quick browse of Wikipedia showed me that the
colon as division sign is common in Ukraine, Russia, Sweden and Germany
too. (Thus, English Wikipedia fittingly acknowledges that 'In some
non-English-speaking cultures, a divided by b is written a : b.' [9])

In Hungary it is the notation of inline division taught in elementary
school, horizontal bar employed for built-up fractions. In upper
classes and in everyday use solidus seems to be much more common.



Thanks,

A./

Re: Too narrowly defined: DIVISION SIGN COLON

2012/7/10 Leif Halvard Silli xn--mlform-...@xn--mlform-iua.no:
 Philippe Verdy, Tue, 10 Jul 2012 13:50:03 +0200:
 2012/7/10 Leif Halvard Silli:
 Asmus Freytag, Mon, 09 Jul 2012 19:32:47 -0700:
 The European use (this is not limited to Scandinavia)

 Thanks. It seems to me that that this tradition is not without a link
 to the (also) European tradition of *not* using the DIVISION SIGN (÷)
 for division.

 Why European ?

 We have 3 accounts which say that is European: I, Jukka and Asmus. It
 might be spread wider ... But perhaps your point was that it is more
 narrow? ;-)

Certainly more narrow. which is probably only for Nordic (Baltic?)
European countries. I just discovered this usage in this discussion.

At least in France we have never learnt that DIVISION SIGN (÷) could
be used for noting the substraction (we have very little interaction
with Nordic European languages, as all other languages around France
apparently have the same conventions for noting operators in their
languages : English, Dutch, German, Italian, Spanish ; and even Arabic
when it is still a large minority language in Metropolitan France or
in French overseas of the Indian Ocean).

I also doubbt that Russian even uses this Nordic convention.

At school (in the 1970's when I was a child) the DIVISION SIGN (÷) was
the first symbol ever tought for noting a division in an horizontal
formula. Long before the slash (/, independapntly of its encoding and
visual length), and then much later with the top-bottom notation using
an horizontal line. The division sign denotes in fact this long
horizontal linen where the dots are visually indicating the placements
of the operands.

But the first notation taught was this one:

: dividend| divisor
:   - partial product  +---
:   --   | quotient
: intermediate remainder  |
:  ...   |
:remainder  |

which was used to learn how to compute manually a division, whose
computed result could then be given using the horizontal formula with
the DIVISION SIGN (÷). We did not have calculators (they were
initially banned in French schools, we had to use paper and pen, or
learn to compute in our heads...) The first calculators were
authorized at end of the 1970's in secondary schools (but they were
stictly limited as their cost was still too expensive at this time for
many families).

All calculators appeared in France using the DIVISION SIGN (÷). This
is still true today (much more frequent than the slash which is only
seen and used on mechanical PC keyboards, but not even on virtual
keyboards on-screen used by calculator applications on PC or on
smartphones, even when they are localized in French).

The minus sign has always been taught as an horizontal line matching
the metrics of the plus sign (notations of neative numbers between
parentheses was used up to the end of the 1960's in some professional
accountings, but the traditional presentation does not even use
negative numbers but separate columns for debit/credits, so that all
numbers are positive only). Using  (÷) in French for the substraction
would cause severe confusions (in France, Belgium, Luxembourg,
Switzerland, North Africa, the French overseas in several continents,
and in Canada) !

French and English probably have always used the same conventions in
mathematics (and it may be true as well for German, Dutch, Spanish,
and Italian), if we ignore minor typographic differences (such as
spacing and kerning or historical ligatures).

Re: Too narrowly defined: DIVISION SIGN COLON

2012/7/10 Asmus Freytag asm...@ix.netcom.com:
 Encoding of new characters in not required to address the issue.

I agree. But annotations may help (these annotations should however be
narrowed by language where they are common, otherwise they will cause
other confusions...)

Re: Too narrowly defined: DIVISION SIGN COLON

May be we could add new resources in the CLDR for specifying the
prefered characters used by the four basic maths operators (normally
we already have the specifiation for the uniary plus and minus signs,
but I'm not sure that this implies their use for noting the binary
operators used in additions and substractions).

Note that several characters could be listed, the first one being the
preferred one, others being also possible when they don't create
confusions, for usual simple mathematical notations.

For scientific papers however these resources will not be used : each
operator uses the international conventions (if there's no prior
définition) and have very precise glyphs that must be consistent
within each document or even between collections of related documents
: if the symbols need to be differentiated (e.g. a middle dot, an
asterisk, an x-like symbol centered on the mathematical line, they
have their own initial definition in the document or in an explicit
reference, to disambiguate things). Those scientific papers however
are most often composed with TeX (or some visual formula editors which
do not produce plain text) and not initially composed using the UCS
encoding.

2012/7/10 Philippe Verdy verd...@wanadoo.fr:
 2012/7/10 Asmus Freytag asm...@ix.netcom.com:
 Encoding of new characters in not required to address the issue.

 I agree. But annotations may help (these annotations should however be
 narrowed by language where they are common, otherwise they will cause
 other confusions...)

Re: Too narrowly defined: DIVISION SIGN COLON


On 7/9/2012 11:04 PM, Jukka K. Korpela wrote:

2012-07-10 5:32, Asmus Freytag wrote:


There are many characters that are used in professional mathematical
typesetting (division slash being one of them) that need to be narrowly
distinguished from other, roughly similar characters.


Typographic differences can be made at glyph selection level, too, or 
even in font design and choice of font. Typesetting systems like TeX 
and derivatives have been very successful along such lines.


TeX and similar systems can get the correct appearance, but they do not 
have the same benefit of a universal encoding of the semantic 
distinction that underlies these variations in appearance.



Such narrowly defined characters are not aimed at the general user, and
it's totally irrelevant whether or not such a character ever becomes
popular.


Popularity is relative to a population. When I wrote that “narrow 
semantics does not make characters popular”, relating to the case of 
DIVISION SLASH, I referred to popularity among people who could 
conceivably have use for the characters. I don’t think there’s much 
actual use of DIVISION SLASH in the wild. And this was about a case 
where the distinction is not only semantic (actually the Unicode 
standard does not describe the semantic side of the matter except 
implicitly via things like Unicode name and General Category of the 
character) but also has, or may have, direct impact on rendering.


I don't know, I would ask mathematical publishers whether they use 
ordinary or division slash.





Very early in the design cycle for Unicode there
was a request for encoding of a decimal period, in distinction to a full
stop. The problem here is that there is no visual distinction


This is more or less a vicious circle, and the starting point isn’t 
even true. In British usage, the decimal point is often a somewhat 
raised dot, above the baseline. But even if we assume that no 
distinction *had been made* before the decision, the decision itself 
implied that no distinction *can be made* by choice of character.


Encoding the same appearance (shape) as two separate characters is 
something that the Unicode standard reserves to well-motivated 
exceptions, such as the multiple encoding of the shape E for the 
Latin, Greek and Cyrillic scripts. You don't need to look further that 
the issues raised with spoofing of internet identifiers to see that 
there are strong downsides to duplicate encoding. This is particularly 
true, when the distinctions in usage are mere notational conventions and 
not as fundamental as script membership.


If a different decision had been made, people could choose to use a 
decimal point character, or they could keep using just the ambiguous 
FULL STOP character. Font designers could make them identical, or they 
could make them different. But most probably, most people would not 
even be aware of the matter: they would keep pressing the keyboard key 
labeled with “.” – that is, the decimal point character would not have 
much popularity. In British typesetting, people would probably still 
use whatever methods they now use to produce raised dots.


A nice argument can be made for encoding a *raised* decimal dot (if it's 
not representable by any number of other raised dots already encoded). 
Clearly, in the days of lead typography, a British style decimal dot 
would have been something that was a distinct piece of lead from a 
period. In the end, no such request was made.



Unicode has relatively consistently refused to duplicate encodings in
such circumstances, because the point about Unicode is not that one
should be able to encode information about the intent that goes beyond
what can be made visible by rendering the text. Instead, the point about
Unicode is to provide a way to unambiguously define enough of the text
so that it becomes legible. How legible text is then understood is
another issue.


That’s a nice compact description of the principle, but perhaps the 
real reasons also include the desire to avoid endless debates over 
“semantics”. Some semantic differences, like the use of a character as 
a punctuation symbol vs. as a mathematical symbol, are relatively 
clear. Most semantics differences that can be made are not that clear 
at all.


Being able to encode an intent that is not directly visible to a reader 
of a rendered text has issues that go beyond the niceties of debating 
semantics. There are some cases where the downsides of that are (nearly) 
unavoidable, and duplicate encoding is - in the end - the better answer. 
But notational conventions usually don't qualify, because it's the 
sharing of that convention between reader and writer that makes the 
notation what it is.



Because of that, there was never any discussion whether the ! would have
to be re-encoded as factorial. It was not.


This implies that if anyone thinks that the factorial symbol should 
look different from a normal exclamation mark, to avoid ambiguity (as 
in

Re: Too narrowly defined: DIVISION SIGN COLON

2012-07-10 Thread Julian Bradfield

On 2012-07-10, Asmus Freytag asm...@ix.netcom.com wrote:
 On 7/10/2012 3:50 AM, Leif Halvard Silli wrote:
 Asmus Freytag, Mon, 09 Jul 2012 19:32:47 -0700:
 The European use (this is not limited to Scandinavia)
 Thanks. It seems to me that that this tradition is not without a link
 to the (also) European tradition of *not* using the DIVISION SIGN (÷)
 for division.

 Is it _ever_ used for division? I'm curious, right now I can't recall 
 ever having seen an example.

Depends whether you think Britain is in Europe;-)

-- 
The University of Edinburgh is a charitable body, registered in
Scotland, with registration number SC005336.

Re: Too narrowly defined: DIVISION SIGN COLON

2012-07-10 Thread Hans Aberg

On 10 Jul 2012, at 21:30, Asmus Freytag wrote:

 On 7/10/2012 3:50 AM, Leif Halvard Silli wrote:
 Asmus Freytag, Mon, 09 Jul 2012 19:32:47 -0700:
 The European use (this is not limited to Scandinavia)
 Thanks. It seems to me that that this tradition is not without a link
 to the (also) European tradition of *not* using the DIVISION SIGN (÷)
 for division.
 
 Is it _ever_ used for division? I'm curious, right now I can't recall ever 
 having seen an example.

The WP Obelus article says that it was used as a sign for division in 1659, 
otherwise used for subtraction, continued in Norway, and until recently, in 
Denmark.

Hans


https://en.wikipedia.org/wiki/Obelus

Re: Too narrowly defined: DIVISION SIGN COLON


On 7/10/2012 1:38 PM, Julian Bradfield wrote:

On 2012-07-10, Asmus Freytag asm...@ix.netcom.com wrote:

On 7/10/2012 3:50 AM, Leif Halvard Silli wrote:

Asmus Freytag, Mon, 09 Jul 2012 19:32:47 -0700:

The European use (this is not limited to Scandinavia)

Thanks. It seems to me that that this tradition is not without a link
to the (also) European tradition of *not* using the DIVISION SIGN (÷)
for division.

Is it _ever_ used for division? I'm curious, right now I can't recall
ever having seen an example.

Depends whether you think Britain is in Europe;-)


That's a lovely question...

A./

Re: Too narrowly defined: DIVISION SIGN COLON

2012-07-10 Thread Richard Wordingham

On Tue, 10 Jul 2012 14:14:03 -0700
Asmus Freytag asm...@ix.netcom.com wrote:

  Depends whether you think Britain is in Europe;-)

 That's a lovely question...

Well if France isn't - Philippe Verdy says he has used '÷' for division
- I don't think Britain can be.

Richard.

Re: Too narrowly defined: DIVISION SIGN COLON

2012/7/11 Asmus Freytag asm...@ix.netcom.com:
 U+00B7 MIDDLE DOT
 * also used to denote multiplication, for that usage 22C5 · DOT OPERATOR is
 preferred

* also used in Catalan as a right-side diacritic added after a LATIN LETTER L.
* also used in some languages as a syllabic or morphemic separation
hyphen (distinct from the hyphen used to link compound words) for
breaking words on margin boundaries.

(Reformulate my poor English).

Re: Too narrowly defined: DIVISION SIGN COLON

I would disagree about the preference for ratio; I think it is a historical
accident in Unicode.

What people use and have used for ratio is simply a colon. One writes 3:5,
and I doubt that there was a well-established visual difference that
demanded a separate code for it, so someone would need to write 3∶5 instead.

Mark https://plus.google.com/114199149796022210033
*
*
*— Il meglio è l’inimico del bene —*
**



On Tue, Jul 10, 2012 at 3:22 PM, Asmus Freytag asm...@ix.netcom.com wrote:

 U+2236 RATIO
 * Used in preference to 003A : to denote division or scale

Re: Too narrowly defined: DIVISION SIGN COLON

2012-07-10 Thread Ken Whistler


On 7/10/2012 4:22 PM, Mark Davis ☕ wrote:
I would disagree about the preference for ratio; I think it is a 
historical accident in Unicode.




Not really.

The following pairs dating from Unicode 1.0 were deliberate:

U+002D HYPHEN-MINUS
U+2212 MINUS SIGN

U+002F SOLIDUS (Unicode 1.0 called it SLASH)
U+2215 DIVISION SLASH

U+005C REVERSE SOLIDUS (Unicode 1.0 called it BACKSLASH)
U+2216 SET MINUS

U+003A ASTERISK
U+2217 ASTERISK OPERATOR

U+25E6 WHITE BULLET
U+2218 RING OPERATOR

U+2022 BULLET
U+2219 BULLET OPERATOR

U+007C VERTICAL BAR
U+2223 DIVIDES

U+2016 DOUBLE VERTICAL BAR
U+2225 PARALLEL TO

U+003A COLON
U+2236 RATIO

U+007E TILDE
U+223C TILDE OPERATOR

U+00B7 MIDDLE DOT
U+22C5 DOT OPERATOR

If anything, the accident is that the use of ! for factorial was not
distinguished with a separate symbol character. I don't recall the
argument in detail -- it was discussed. But I suspect that it came down
to most of the math operators being in principle distinguishable because
they are rendered on the math centerline, rather than the baseline,
whereas nobody could think of a good reason for a layout distinction
for the factorial -- so it fell instead into the bucket already occupied
by . as full stop versus decimal point (versus record separator versus...)

Now subsequent history has since led to more systematic distinctions,
both in use and in glyph design, for some of the pairs listed above.
For example, the two tildes generally look different. The SET MINUS was
discovered to actually be distinct from a backslash, with a different
angle and length. And so on. So that has whittled down the list of
characters that people, after the fact, come to think of as accidental
duplicates.

But trying to rationalize these decisions by examining only the latest
charts, while ignoring the history of how these distinctions came about
in the first place is not a productive direction, IMO.

Incidentally, one of the reasons the set of symbols in the U+2200
Mathematical Operators block got a somewhat different treatment than
generic punctuation or other symbols or combining marks, when it comes
to unification versus non-unification decisions back in the original
draft charts in 1989 and 1990 had something to do with the intuition
back then that having unambiguous encodings for the math operators
would be important for machine processing of mathematical data
(as in algebra systems). It isn't so clear now, in retrospect, whether
some of the disunifications were a good idea or not. But those
decisions are what we have inherited in the standard now, for better
or worse.

--Ken

Re: Too narrowly defined: DIVISION SIGN COLON

2012/7/11 Mark Davis ☕ m...@macchiato.com:
 I would disagree about the preference for ratio; I think it is a historical
 accident in Unicode.

 What people use and have used for ratio is simply a colon. One writes 3:5,
 and I doubt that there was a well-established visual difference that
 demanded a separate code for it, so someone would need to write 3∶5 instead.

Is that me or I see 3 vertical dots in your last line (instead of 2
vertical dots for the usual colon) ? This unusual sign is certainly
NOT the one used to note scales on maps or ratios. We use and see the
2-dots colon almost always.

The 3-dots symbol (or punctuation) is clearly distinct, and not an
accident. It is very uncommon. It is not a duplicate encoding. May be
it is used for noting ratios (I've never seen that) or as
asupplementtary mathematical operator, or as a custom separator
similar in use to the vertical pipe in some contexts that require
several types of separators visually distinct.

Did you type the correct character ?

Re: Too narrowly defined: DIVISION SIGN COLON

I am using the ratio character in the final 3∶5. Whether or not there is a
distinction between that and 3:5, and what that distinction is, seems to
depend entirely on the font in question.

Bizarrely, it does seem to have 3 dots in Lucida Sans.

--
Mark https://plus.google.com/114199149796022210033
*
*
*— Il meglio è l’inimico del bene —*
**



On Tue, Jul 10, 2012 at 5:07 PM, Philippe Verdy verd...@wanadoo.fr wrote:

 2012/7/11 Mark Davis ☕ m...@macchiato.com:
  I would disagree about the preference for ratio; I think it is a
 historical
  accident in Unicode.
 
  What people use and have used for ratio is simply a colon. One writes
 3:5,
  and I doubt that there was a well-established visual difference that
  demanded a separate code for it, so someone would need to write 3∶5
 instead.

 Is that me or I see 3 vertical dots in your last line (instead of 2
 vertical dots for the usual colon) ? This unusual sign is certainly
 NOT the one used to note scales on maps or ratios. We use and see the
 2-dots colon almost always.

 The 3-dots symbol (or punctuation) is clearly distinct, and not an
 accident. It is very uncommon. It is not a duplicate encoding. May be
 it is used for noting ratios (I've never seen that) or as
 asupplementtary mathematical operator, or as a custom separator
 similar in use to the vertical pipe in some contexts that require
 several types of separators visually distinct.

 Did you type the correct character ?

Re: Too narrowly defined: DIVISION SIGN COLON

The main point is that asserting a general preference in an annotation for ∶ to
express a ratio, as Asmus had in his formulation, is simply wrong and
counterproductive. (We are not going to change the world's usage from : to ∶
by fiat; and and the glyphic difference is quite subtle, and missing in a
great many fonts. Compare that with the difference between hyphen-minus and
minus, which is much more pronounced, and much better carried across fonts.)

The most that we could say is that in certain mathematical contexts ∶ is
preferred to : for expressing ratios, not that it is generally preferred.

By the way, here's your list with visible characters instead of the U+'s.

- HYPHEN-MINUS
− MINUS SIGN

/ SOLIDUS (Unicode 1.0 called it SLASH)
∕ DIVISION SLASH

\ REVERSE SOLIDUS (Unicode 1.0 called it BACKSLASH)
∖ SET MINUS

* ASTERISK *// you had U+003A = :  instead of *.*
∗ ASTERISK OPERATOR

◦ WHITE BULLET
∘ RING OPERATOR

• BULLET
∙ BULLET OPERATOR

| VERTICAL BAR
∣ DIVIDES

‖ DOUBLE VERTICAL BAR
∥ PARALLEL TO

: COLON
∶ RATIO

~ TILDE
∼ TILDE OPERATOR

· MIDDLE DOT
⋅ DOT OPERATOR

--
Mark https://plus.google.com/114199149796022210033
*
*
*— Il meglio è l’inimico del bene —*
**



On Tue, Jul 10, 2012 at 5:05 PM, Ken Whistler k...@sybase.com wrote:

  On 7/10/2012 4:22 PM, Mark Davis ☕ wrote:

 I would disagree about the preference for ratio; I think it is a
 historical accident in Unicode.


 Not really.

 The following pairs dating from Unicode 1.0 were deliberate:

 U+002D HYPHEN-MINUS
 U+2212 MINUS SIGN

 U+002F SOLIDUS (Unicode 1.0 called it SLASH)
 U+2215 DIVISION SLASH

 U+005C REVERSE SOLIDUS (Unicode 1.0 called it BACKSLASH)
 U+2216 SET MINUS

 U+003A ASTERISK
 U+2217 ASTERISK OPERATOR

 U+25E6 WHITE BULLET
 U+2218 RING OPERATOR

 U+2022 BULLET
 U+2219 BULLET OPERATOR

 U+007C VERTICAL BAR
 U+2223 DIVIDES

 U+2016 DOUBLE VERTICAL BAR
 U+2225 PARALLEL TO

 U+003A COLON
 U+2236 RATIO

 U+007E TILDE
 U+223C TILDE OPERATOR

 U+00B7 MIDDLE DOT
 U+22C5 DOT OPERATOR

 If anything, the accident is that the use of ! for factorial was not
 distinguished with a separate symbol character. I don't recall the
 argument in detail -- it was discussed. But I suspect that it came down
 to most of the math operators being in principle distinguishable because
 they are rendered on the math centerline, rather than the baseline,
 whereas nobody could think of a good reason for a layout distinction
 for the factorial -- so it fell instead into the bucket already occupied
 by . as full stop versus decimal point (versus record separator
 versus...)

 Now subsequent history has since led to more systematic distinctions,
 both in use and in glyph design, for some of the pairs listed above.
 For example, the two tildes generally look different. The SET MINUS was
 discovered to actually be distinct from a backslash, with a different
 angle and length. And so on. So that has whittled down the list of
 characters that people, after the fact, come to think of as accidental
 duplicates.

 But trying to rationalize these decisions by examining only the latest
 charts, while ignoring the history of how these distinctions came about
 in the first place is not a productive direction, IMO.

 Incidentally, one of the reasons the set of symbols in the U+2200
 Mathematical Operators block got a somewhat different treatment than
 generic punctuation or other symbols or combining marks, when it comes
 to unification versus non-unification decisions back in the original
 draft charts in 1989 and 1990 had something to do with the intuition
 back then that having unambiguous encodings for the math operators
 would be important for machine processing of mathematical data
 (as in algebra systems). It isn't so clear now, in retrospect, whether
 some of the disunifications were a good idea or not. But those
 decisions are what we have inherited in the standard now, for better
 or worse.

 --Ken

Re: Too narrowly defined: DIVISION SIGN COLON

2012-07-10 Thread Martin J. Dürst


On 2012/07/11 4:37, Asmus Freytag wrote:


I recall, with certainty, having seen the : in the context of
elementary instruction in arithmetic,
as in 4 : 2 = ?, but am no longer positive about seeing ÷ in the same
context.


I remember this very well. In grade school, we had to learn two ways to 
divide, which were distinguished by using two symbols, ':' and '÷', and 
different verbs, the German equivalents of divide and measure.


I'll explain the difference with two examples:

a) There are 12 apples, and four kids. How many apples does each kid 
get? [answer: 3 apples]


b) There are 12 apples, and each kid gets 4 of them. For how many kids 
will that be enough? [answer: for 3 kids]


I think a) was called 'divide' and b) was called 'measure', but I can't 
remember which symbol was used for which.


When we were learning this, I thought it was a bit silly, because the 
numbers were the same anyway. It seems to have been based on the 
observation that at a certain stage in the development of arithmetic 
skills, children may be able to do division (in the general, numeric 
sense) one way but not the other, or that they get confused about the 
units in the answer. But while such an observation may be true, I don't 
think such a stage lasts very long, definitely not as long as we had to 
keep the distinction (at least through second and third grade).


Also, I think this may have been a local phenomenon, both in place and 
time. But if one searches for geteilt gemessen, one gets links such as 
this:

http://www.niska198.de.tl/Gemessen-oder-Geteilt-f-.htm
So maybe some of this is still in use.

Regards,   Martin.

Re: Too narrowly defined: DIVISION SIGN COLON

2012-07-10 Thread Khaled Hosny

They are spaced differently. Attached how they are rendered by TeX,
using its default spacing rules, the first is the ratio (which is spaced
as a relational symbol) and the second is the colon (which is spaced as
punctuation mark), both in math mode, and the last one is the colon in
text mode.

On Tue, Jul 10, 2012 at 04:22:06PM -0700, Mark Davis ☕ wrote:
 I would disagree about the preference for ratio; I think it is a historical
 accident in Unicode. 
 
 What people use and have used for ratio is simply a colon. One writes 3:5, and
 I doubt that there was a well-established visual difference that demanded a
 separate code for it, so someone would need to write 3∶5 instead.
 
 Mark
 
 — Il meglio è l’inimico del bene —
 
 
 
 On Tue, Jul 10, 2012 at 3:22 PM, Asmus Freytag asm...@ix.netcom.com wrote:
 
 U+2236 RATIO
 * Used in preference to 003A : to denote division or scale
 
 
attachment: texput.png

Re: Too narrowly defined: DIVISION SIGN COLON

That is, they *may be* spaced differently (depending on the font and
environment).

I'm not against pointing to RATIO for specific math contexts, but to tell
Joe Smith that he should be using a different character to say that the
ratio of gravel to sand should be 3:1 is artificial and pointless.

--
Mark https://plus.google.com/114199149796022210033
*
*
*— Il meglio è l’inimico del bene —*
**



On Tue, Jul 10, 2012 at 5:51 PM, Khaled Hosny khaledho...@eglug.org wrote:

 They are spaced differently. Attached how they are rendered by TeX,
 using its default spacing rules, the first is the ratio (which is spaced
 as a relational symbol) and the second is the colon (which is spaced as
 punctuation mark), both in math mode, and the last one is the colon in
 text mode.

 On Tue, Jul 10, 2012 at 04:22:06PM -0700, Mark Davis ☕ wrote:
  I would disagree about the preference for ratio; I think it is a
 historical
  accident in Unicode.
 
  What people use and have used for ratio is simply a colon. One writes
 3:5, and
  I doubt that there was a well-established visual difference that
 demanded a
  separate code for it, so someone would need to write 3∶5 instead.
 
  Mark
 
  — Il meglio è l’inimico del bene —
 
 
 
  On Tue, Jul 10, 2012 at 3:22 PM, Asmus Freytag asm...@ix.netcom.com
 wrote:
 
  U+2236 RATIO
  * Used in preference to 003A : to denote division or scale

Re: Too narrowly defined: DIVISION SIGN COLON