#12957: Categories for finite (enumerated) sets
-------------------------------+------------------------
Reporter: nthiery | Owner: nthiery
Type: enhancement | Status: new
Priority: major | Milestone: sage-6.4
Component: categories | Resolution:
Keywords: | Merged in:
Authors: | Reviewers:
Report Upstream: N/A | Work issues:
Branch: | Commit:
Dependencies: #12913 | Stopgaps:
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Old description:
> There still remains a lot of finite (enumerated) sets that are not in the
> appropriate categories::
>
> {{{
> sage: CartesianProduct([1,2],[2,3]).category()
> Category of sets
> sage: Permutations().category()
> Category of sets
> sage: Set([1,2,3]).category()
> Category of sets
> sage: (GF(3) ^ 2) in FiniteEnumeratedSets()
> False
> sage: MatrixSpace(GF(3),2) in FiniteEnumeratedSets()
> False
> sage: DirichletGroup(5).category()
> Category of sets
> sage: LatticePolytope(matrix(ZZ, [[1,1],[0,1]])).category()
> Category of objects
> }}}
>
> By the way, one should fix
> {{{
> sage: M = Family(NonNegativeIntegers(), Permutations)
> sage: M.cardinality()
> }}}
> to uses len internally.
>
> See also: #12913
New description:
There still remains a lot of finite (enumerated) sets that are not in the
appropriate categories::
{{{
sage: CartesianProduct([1,2],[2,3]).category()
Category of enumerated sets
sage: Set([1,2,3]).category()
Category of sets
sage: (GF(3) ^ 2) in FiniteEnumeratedSets()
False
sage: MatrixSpace(GF(3),2) in FiniteEnumeratedSets()
False
sage: LatticePolytope(matrix(ZZ, [[1,1],[0,1]])).category()
Category of objects
}}}
See also: #12913
The following examples were originally in the ticket description but are
good on sage-6.9.beta1
{{{
sage: Permutations().category()
Category of infinite enumerated sets
sage: DirichletGroup(5).category()
Category of finitely generated finite commutative groups
}}}
--
Comment (by vdelecroix):
On sage-6.9.beta1
--
Ticket URL: <http://trac.sagemath.org/ticket/12957#comment:5>
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