Re: [Jchat] How close is J to APL?

Regarding 0-origin and 1-origin indexing. It helped me to mentally distinguish between cardinal numbers, 0 1 2 3 . . . , pronounced "zero", "one", "two", "three", and so on, and ordinal numbers, 1 2 3 4 . . . , pronounced: "first", "second", "third", "fourth", and so on, or alternatively

Re: [Jchat] How close is J to APL?

The terms "ordinal number" and "cardinal number" has advanced mathematical meanings in the theory of infinite sets and transfinite numbers, but the words also have ancient meanings in grammar. The semantics of a cardinal number is to count the elements of a finite set, and the semantics of an

Re: [Jchat] How close is J to APL?

re has been some debate about the exact year when the actual aforementioned event happened: 4 BC, 1 BC, AD 1, ... On Sat, May 19, 2018 at 9:38 AM, 'Bo Jacoby' via Chat <c...@jsoftware.com> wrote: > The terms "ordinal number" and "cardinal number" has advanced mathemati

Re: [Jchat] How close is J to APL?

mr Jose Mario Quintana remarks that stopwaches and odometers are 0-origin devices. Today is the 24th day in the 5th month in the 2018th year. The ordinal numbers begin at "first". But a stopwatch would show that 2017 years, 4 months and 23 days have passed. Cardinal numbers begin at zero. A J

Re: [Jchat] J, APL, or calendars?

Ordinal numbers are not considered in J. The expression 2{y should not be read as "take the second element of y" but as "skip 2 elements and take the left element of y".  Ordinal Fractions use one-digit ordinal numbers for indexing. There are but nine one-digit ordinal numbers: 1 2 3 4 5 6 7 8

Re: [Jchat] How close is J to APL?

> Astronomical year numbering > > https://en.wikipedia.org/wiki/Astronomical_year_numbering > > > > PS.  There has been some debate about the exact year when the actual > > aforementioned event happened: 4 BC, 1 BC, AD 1, ... > > > > > > On Sat, May 19, 2018

Re: [Jchat] J, APL, or calendars?

used me then. No wonder kids have difficulty grasping the concept of zero. On Fri, Jun 8, 2018, 8:34 AM Björn Helgason wrote: > beenary numbers > > https://m.phys.org/news/2018-06-scientists-bees-concept.html > > On Fri, 8 Jun 2018 07:40 'Bo Jacoby' via Chat, wrote: >

Re: [Jchat] J, APL, or calendars?

letters to represent numbers from > one to nine with no zero: > > alpha  beta  gamma  delta  epsilon  digamma  zeta  eta  theta > > They didn’t need to use 0 for higher values because much like Romans they had > symbols for higher values. > > However this was not an e

Re: [Jchat] J, APL, or calendars?

9 system could be either. You suddenly use 0 when you illustrate tables. You do not show how to access particular rows or columns or elements from a table but instead use vague terms upper, lower, left, right without knowing the number of rows or columns.. Why not the concept of arrays wit

Re: [Jchat] How close is J to APL?

NB. This is the ordinal fraction way of solving the Transylvanian problem. NB. (My earlier solution had an error) NB. First the table of explanations.    NB. 0001 Minna is human NB. 0002 Minna is vampire NB. 0010 Minna is sane NB. 0020 Minna is insane NB. 0100 Lucy is human NB. 0200 Lucy is

Re: [Jchat] J, APL, or calendars?

en 30. maj 2018 skrev 'Bo Jacoby' via Chat : "2018 is the ninth year of the second decade etc"? No!The first decade consist of the years 1 2 3 4 5 6 7 8 9 10.  The 202. decade consist of the years 2011  2012 2013 2014 2015 2016 2017 2018 2019 2020.  So 2018 is the 8. year of th

Re: [Jchat] J, APL, or calendars?

: And months are not centuries. Nor do centuries have periodically repeating names. They are different abstractions. Though both can be used to describe time, they do not describe it in the same way. Thanks, -- Raul On Wed, May 30, 2018 at 5:38 PM, 'Bo Jacoby' via Chat wrote: > The mon

Re: [Jchat] J, APL, or calendars?

. They are not, however, a Gregorian century. Nor, a Julian century. I trust you can see the distinctions. -- Raul On Wed, May 30, 2018 at 3:36 PM, 'Bo Jacoby' via Chat wrote: > "tjugohundratalen" means the years 2000 . . 2099. This period is not a > century, even if it

Re: [Jchat] J, APL, or calendars?

e romans, and pre-dates the invention of > the zero. > > Thanks, > > — > Raul > > On Wednesday, May 30, 2018, 'Bo Jacoby' via Chat > wrote: > > > Are you missing the point? The ordinal numbers used for counting > centuries > > and years are  1. 2. 3

Re: [Jchat] J, APL, or calendars?

nguages associate many concrete concepts with individual words. Thanks, -- Raul On Wed, May 30, 2018 at 5:57 PM, 'Bo Jacoby' via Chat wrote: > Centuries within millenia have periodically repeating names: first century . > . tenths century. They describe time intervals in exactly the same way. Today &

Re: [Jchat] J, APL, or calendars?

{ A ┌──┬─┬──┬─┐ │Second│Third│Fourth│Fifth│ └──┴─┴──┴─┘ On Sat, May 26, 2018 at 12:38 AM, 'Bo Jacoby' via Chat wrote: > Ordinal numbers are not considered in J. The expression 2{y should not be > read as "take the second element of y" but as "ski

Re: [Jchat] J, APL, or calendars?

year 5778. > > Etc... > > (Translation: the answer here depends on your religious beliefs) > > I hope this helps. > > Have a nice day. > > Thanks, > > — > Raul > > On Tuesday, May 29, 2018, 'Bo Jacoby' via Chat wrote: > > > Do we agree that this year,

Re: [Jchat] J, APL, or calendars?

I was refering to "ordinal number" as explained in the wiktionary:"First, second and third are the ordinal numbers corresponding to one, two and three". That is not my invention. The ordinal fraction is my invention. Den 17:56 torsdag den 31. maj 2018 skrev

Re: [Jchat] J, APL, or calendars?

s, and that ordinal numbers do not occur in J.  Den 15:57 torsdag den 31. maj 2018 skrev 'Bo Jacoby' via Chat : "If someone is 8 years old, she is in her 9th year, I would say. And what do you say?" I agree. The number of years that have passed is 8, and this year is her

Re: [Jchat] J, APL, or calendars?

Let me tell you how calendars are treated with ordinal fractions. Consider the years from 1 to 5000. Any year is a year in a decennium in a century in a  millenium,  The year 2010 is the tenth year in the first decennium in the first century in the third millenium.    

Re: [Jchat] J, APL, or calendars?

useful.  Den 21:06 torsdag den 31. maj 2018 skrev Donna Y : Are you re-inventing the rational numbers by another name? Donna Y dy...@sympatico.ca > On May 31, 2018, at 12:10 PM, 'Bo Jacoby' via Chat wrote: > > The ord

Re: [Jchat] J, APL, or calendars?

I do not "bother other people with peculiarities which hinders them to start at 0", but (as everybody else) I do distinguish between cardinal numbers (including 0) and ordinal numbers (starting at "first"). An age is a cardinal number, and a year number is an ordinal number. You are perfectly

Re: [Jchat] J, APL, or calendars?

The proposed calender addresses points in time rather than intervals of time. It does'n address "the twentyfirst century". Before the advent of clocks the hours were addressed by ordinal numbers, like "the eleventh hour", but a clock shows the cardinal number of hours and minutes elapsed since

Re: [Jchat] J, APL, or calendars?

Interesting! Is the zeroth century from year -99 to year 0, or from year -100 to year -1, or from year 0 to year 99? Den 20:54 onsdag den 6. juni 2018 skrev Donna Y : Notice the the year 0 in Astronomical year numbering is > Fred Espanak of NASA

Re: [Jchat] J, APL, or calendars?

Thanks to Donna for the interest and for the information.  Ordinal Fractions is an improvement to the idea behind the Universal Decimal Classification (UDC). Consider this example from wikipedia. 51 Mathematics 510Fundamental and general considerations of mathematics 511Number

Re: [Jchat] J, APL, or calendars?

How come the mail system removed the new line characters? Den 9:48 torsdag den 7. juni 2018 skrev 'Bo Jacoby' via Chat : Thanks to Donna for the interest and for the information.  Ordinal Fractions is an improvement to the idea behind the Universal Decimal Classification (UDC

Re: [Jchat] J, APL, or calendars?

   

Re: [Jchat] J, APL, or calendars?

"If someone is 8 years old, she is in her 9th year, I would say. And what do you say?" I agree. The number of years that have passed is 8, and this year is her 9th. Christ is 2017 years old in this year 2018.  Den 15:50 torsdag den 31. maj 2018 skrev 'Bo Jacoby' via Chat :    (4#10)

Re: [Jchat] Fwd: Re: The n-cell model of an array

Erling Hellenäs asked: "It's old hierarchical databases? At least related? Could the algebra proposed help us handle them?" I think yes. Ordinal Fraction databases handles arrays and hierarchies equally painlessly. An ordinal fraction database is like a sparse array where the indexes are

Re: [Jchat] ordinal fractions

It is not easy to find realistic examples small enough for demonstration, but consider a child dressing for playing outdoors in the cold. He must put on a  flying suit, boots, hat, and mittens. The order is not completely free, because he cannot take on the flying suit once he has put on the

Re: [Jchat] ordinal fractions

Yes, you got it right. Well done! But I omit blanks between digits in the ordinal fractions.  And zeroes to the right may be omitted.   a 1  b 11  c 12  d 13  e 2  q Thank you! Bo Den 12:52 fredag den 22. december 2017 skrev R.E. Boss : 0 1 1  c 0 1 2  d 0 1 3  e

Re: [Jchat] A mention of J and the Computers and Mathematical Notation paper

Regarding matematical notation.  J is too rich for beginners.  We first learn addition, subtraction, multiplication and division. Later we use the minus sign for negative numbers, like -2. Then we do not need subtraction any more. The difference is written  7+-2, This was not taught in school. 

Re: [Jchat] A mention of J and the Computers and Mathematical Notation paper

's > only when you combine it with other topics that it can become useful. > > Thanks, > > -- > Raul > > On Sat, Nov 3, 2018 at 5:31 AM 'Bo Jacoby' via Chat > wrote: > > > >  Regarding matematical notation. > > J is too rich for beginners. > > We fi

Re: [Jchat] the advantage of J

8 ÷ 2(2 + 2) is supposed to mean either 8 ÷ (2(2 + 2))  or (8 ÷ 2)(2 + 2) . To avoid misunderstanding, write either 8 ÷ (2(2 + 2))  or (8 ÷ 2)(2 + 2) rather than 8 ÷ 2(2 + 2) . J allows redundant parentheses: either 8%(2*(2+2)) or (8%2)*(2+2) rather than  8%2*2+2 or (8%2)*2+2 . Den

Re: [Jchat] the advantage of J

Thanks Roger! Three conspiracy theorists went into a bar.  That can't be a coincidence.  Den fredag den 27. september 2019 14.21.39 CEST skrev Roger Hui : > A mathematician walked into a bar. I can't leave this unchallenged. :-) A physicist, a biologist, and a mathematician sat on a

Re: [Jchat] J "like-wow"s?

These are my favorite one-liners.    deduce =: %~`*`:3"2@(,:(%:@*-.))@(+/@[%~1,,:)    predict =: (deduce~-@>:)~    induce =: (,:0:)+[predict(-+/)~ Examples. First line of result: mean values. Second line of result: standard deviations.    50 30 20 deduce 9 NB. from the population, deduce

Re: [Jchat] sandpiles! (new J video)

Hi Michal. It's interesting. But you talk too fast for me to understand. Thanks. Bo. Den tirsdag den 24. marts 2020 13.24.25 CET skrev Michal Wallace : I made a new video. It's about sandpiles -- a simple cellular automaton with interesting mathematical properties. This one is more

Re: [Jchat] sandpiles! (new J video)

Thank you Raul! I didn't know that. /Bo. Den tirsdag den 24. marts 2020 14.30.10 CET skrev Raul Miller : You can slow down playback using the gear icon in the lower right of the youtube player. Try 0.75 speed, for example. Thanks, -- Raul On Tue, Mar 24, 2020 at 8:59 AM 'Bo Jacoby

Re: [Jchat] [Jprogramming] J and Spreadsheets

Chris requested this discussion moved from programm...@jsoftware.com to c...@jsoftware.com.  This is Hauke's example. I think the intention is to insert a record in the top. This program has an edit-mode allowing to change, insert and delete data and line numbers. Changing line number 3050

Re: [Jchat] Ordinal Fractions

Thanks to Art Anger for the comments. Counting to more than nine needs more than one digit position, as ten is written 10. Rather than counting 1 2 3 4 5 6 7 8 9 10 you could write 01 02 03 04 05 06 07 08 09 10 such that every number has two digits. Ordinal fractions do not use digit zero for

Re: [Jchat] Euler Project problems 762 & 763

Where does the multiplicity arise? For convenience I transpose the matrix. The first state is1000  . . . It is made into (N=1) 1100 . . . Now there are two possibilities for the next move: (N=2) 01001100 . . . and 1110 . . . So C(2)=2 See what I mean? /Bo. Den

Re: [Jchat] Euler Project problems 762 & 763

The email removed carriage returns. I insert them here. Where does the multiplicity arise? For convenience I transpose the matrix. The first state is 1000   . . . It is made into (N=1) 1100  . . . Now there are two possibilities for the next move: (N=2) 0100 1100  . .

Re: [Jchat] Fw: [Jprogramming] DataFrames in J

ess (for hypothetical files other than CREDO). I guess this feels like it's about half way between a compression system and an indexing system. I hope this helps, -- Raul On Mon, Feb 14, 2022 at 4:28 PM 'Bo Jacoby' via Chat wrote: > > Ric requested thoughts on database structure and asked

[Jchat] Fw: [Jprogramming] DataFrames in J

Ric requested thoughts on database structure and asked for examples. Consider this example. https://www.dropbox.com/s/gj8r19hd6exyw3s/Norddata89.pdf?dl=0 The database browser is 8 lines of BASIC. I have not converted it into J. I have no routine in file handling in J. The database example is