Dear Javier, dear all,
On Wed, Oct 28, 2009 at 09:44:33AM -0700, javier wrote:
> I have been reviewing the last categories I had assigned. Here some
> comments
Yippee!
> ordered_sets.py
> Partially ordered or totally ordered? Why not to call it the
> appropriate way then?
Again, that's just how it used to be. Do we have an agreement for
having both:
PartiallyOrderedSets()
TotallyOrderedSets()
I haven't Wikipedia under hand. But since an OrderedMonoid is a
partially ordered set there, I assume that OrderedSets could be an
alias for PartiallyOrderedSets.
Please everybody vote!
> quotient_fields.py
> OK. Remove the # TODO: Algebras(R)
Thanks. Done. The final count down has begun!
6
> right_modules.py
> -31 sage: TestSuite(LeftModules(ZZ)).run()
> +31 sage: TestSuite(RightModules(ZZ)).run()
5
> ring_ideals.py
> OK
4
> rngs.py
> OK
3
> vector_spaces.py
> Concerning the super_categories, why to return Modules(R)? It is not
> a different category. IMO we should return Sets() or something like
> that.
Yes, they are equal. However, as in a previous similar situation
(CommutativeRingIdeals w.r.t. RingIdeals), keeping them separate
allows for putting in Modules(R) all the mathematical information and
code that is generic to any module, and in VectorSpaces(R) those which
are specific to vector spaces. At the same time, from the callers
point of view, typing Modules(QQ) could automatically return
VectorSpaces(QQ).
> Also (concerning the last remark) I was wondering whether is would
> be useful to have a "free modules" category, working in the same way
> as vector spaces, but over an arbitrary ring. For that category it
> would make sense to return "Modules(R)" as a super-category.
That would make sense. We have ModulesWithBasis(R) which somehow plays
this role, even though it's not exactly FreeModules(R), since we
further ask for a distinguished basis.
I added this as a TODO in Modules until someone has a concrete use
case for this category.
Cheers,
Nicolas
--
Nicolas M. Thiéry "Isil" <nthi...@users.sf.net>
http://Nicolas.Thiery.name/
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