#11490: Add a thematic tutorial on coercion and categories
---------------------------------------------------------+------------------
Reporter: SimonKing | Owner:
mvngu
Type: enhancement | Status:
needs_review
Priority: major | Milestone:
sage-5.7
Component: documentation | Resolution:
Keywords: categories coercion thematic tutorial | Work issues:
Report Upstream: N/A | Reviewers:
Authors: Simon King | Merged in:
Dependencies: #14084 | Stopgaps:
---------------------------------------------------------+------------------
Comment (by vdelecroix):
Hello,
I was wondering for such a patch to come! I read it because I am
interested but by far not an expert. Here are some comments for
trac11490-coercion_tutorial.patch, line numbers refer to the patch.
* you may write "and" or "respectively" instead of "resp." (line 34)
* at lines 195-198 there is a kind of magic to test the pickling. You
shoud add few words to explain what's happening.
* I do not like the `class MyFrac(MyFrac)` at lines 462, 812, 882 (but do
not have better option)
* I would like to know why test at line 494 fails while I was able to add
some elements at line 294
* line 678: write "P1 == P2" instead of "P1==P2" (ie add whitespaces on
both sides of "==")
* I do not like your example at line 687 because of
{{{
sage: P1 = QQ['v,w']; P2 = ZZ['w,v']
sage: v1 = P1('v'); w1 = P1('w')
sage: v2 = P2('v'); w2 = P2('w')
sage: (v1 + w2).parent() is P1
True
sage: (v2 + w1).parent() is P1
True
}}}
In other words, P1 is prefered to P2 ! Why is the reason ? I expected
that are natural coercions in both directions then the parent of elements
`a+b` is determined by the parent of `a`. Actually, there is an
explanation in the lines after...
Best,
Vincent
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/11490#comment:9>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
--
You received this message because you are subscribed to the Google Groups
"sage-trac" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
To post to this group, send email to [email protected].
Visit this group at http://groups.google.com/group/sage-trac?hl=en.
For more options, visit https://groups.google.com/groups/opt_out.
