#10963: More functorial constructions
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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, | eb7b486c6fecac296052f980788e15e2ad1b59e4
#10193, #12895, #14516, #14722, | Stopgaps:
#13589, #14471, #15069, #15094, |
#11688, #13394, #15150, #15506 |
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Comment (by SimonKing):
Replying to [comment:468 nthiery]:
> I agree: it's non optimal to have to implement a placeholder category
> MagmasAndAdditiveMagmas just to define the distributive
> axiom. Likewise for the chain
>
DistributiveMagmasAndAdditiveMagmas.AdditiveAssociative.AdditiveCommutative.AdditiveUnital
> I mentioned earlier. But this is well within the scope of the ticket
> which is to go from a potentially exponential number of placeholder
> categories to just a couple.
>
> ...
>
> What I find more annoying is that Sage can't currently be taught that
> MagmasAndAdditiveMagmas is the join of Magmas and AdditiveMagmas,
Exactly! And it is one of the reasons why I prefer to move the whole logic
into a dedicated database of category classes, perhaps based on boolean
polynomial rings. If you input `Magmas*AdditiveMagmas*Distributive`, then
this database would spit out the class that is labelled with this
identifier (wherever it is implemented, as a nested class or in a separate
Python module), and the label would make clear that what we consider is
"apply the `Distributive` axiom to the category labelled
`Magmas*AdditiveMagmas`, which is the join of `Magmas` and
`AdditiveMagmas`.
--
Ticket URL: <http://trac.sagemath.org/ticket/10963#comment:469>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
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