#10963: More functorial constructions
-------------------------------------+-------------------------------------
Reporter: nthiery | Owner: stumpc5
Type: enhancement | Status: needs_review
Priority: major | Milestone: sage-6.1
Component: categories | Resolution:
Keywords: days54 | Merged in:
Authors: Nicolas M. Thiéry | Reviewers: Simon King, Frédéric
Report Upstream: N/A | Chapoton
Branch: | Work issues:
public/ticket/10963 | Commit:
Dependencies: #11224, #8327, | 8045aa4a4b7ada735b3eb6055382f9b341a39f1e
#10193, #12895, #14516, #14722, | Stopgaps:
#13589, #14471, #15069, #15094, |
#11688, #13394, #15150, #15506 |
-------------------------------------+-------------------------------------
Comment (by nbruin):
Replying to [comment:396 vbraun]:
> Or, even better, with stand-alone axiom objects either using a
`@require_axiom(Finite)` decorator or class syntax if you prefer:
> {{{
> sage: class Cs(Category):
> ....: class Finite_or_any_other_name(axioms.Finite):
> ....: class ParentMethods:
> ....: def foo(self):
> ....: print "I am a method on finite C's"
> }}}
There's a peculiarity in this representation of the concept: with this
paradigm
it would be possible to implement multiple `axiom.Finite` subclasses on
`Cs`. I'm not sure that's a desirable property. Although it could express
Wedderburn: The `Finite` and `Commutative` attributes on `DivisionRings`
could
both inherit from both `axiom.Finite` and `axiom.Commutative`. I'm not so
sure
doing this is desirable. I would expect it's better to mandate that every
category can implement an axiom at most once. And using fixed attribute
names
does that naturally, at the expense of forcing name choice.
I wonder if "name clashes" in axioms are ever a real problem. I would hope
that
if two categories `A` and `B` have conflicting ideas over what the axiom
named `d` must mean, then any common supercategory doesn't implement
either
(because it can't carry them). I don't think the different meanings will
ever
clash then.
If there is a common supercategory that implements one of the meanings of
the
axiom then the terminology is genuinely confusing and then the system
rightly
points at a naming clash that needs resolving.
--
Ticket URL: <http://trac.sagemath.org/ticket/10963#comment:405>
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.
For more options, visit https://groups.google.com/groups/opt_out.
