Nicolas,
I found the "dispatch" switch for the Modules(Field) ---> VectorSpaces(Field)
rewriting, and turned this off for default. This will work fine for me.
--Mark
> I am actually running into trouble with this tensor and
> module over field = vector space category mangling.
> Do you have a suggestion for a workaround, so my
> automatic constructions don't get rejected for
> category mismatching?
>
> --Mark
>
> On Tuesday, March 25, 2014 9:42:18 AM UTC-4, Nicolas M. Thiery wrote:
> >
> > On Mon, Mar 24, 2014 at 04:35:49PM -0400, Mark Shimozono wrote:
> > > Here is a probably unintended consequence of
> > > rewriting ModulesWithBasis(QQ) in terms of vector spaces,
> > >
> > > --Mark
> > >
> > > {{{
> > >
> > > sage: cat = ModulesWithBasis(QQ); cat
> > > Category of vector spaces with basis over Rational Field
> > >
> > > sage: cat2 = ModulesWithBasis(QQ).TensorProducts().base_category(); cat2
> > > Category of modules with basis over Rational Field
> > >
> > > sage: cat == cat2
> > > False
> > >
> > > }}}
> >
> > This rewriting is indeed a bit crappy in general Modules ought to be a
> > functorial construction.
> >
> > That being aid, in the case at hand, it's a general behavior whenever
> > a specific category does not implement anything about a given
> > functorial construction:
> >
> > sage: Groups().CartesianProducts().base_category()
> > Category of monoids
> >
> > The advantage is that this avoid creating lots of intermediate
> > categories. The inconvenient is that we are loosing information. In
> > the case of covariant functorial constructions, we could indeed do
> > better at not much cost by returning the intersection of the above
> > with the category of groups. I'll keep that in mind.
> >
> > Cheers,
> > Nicolas
> > --
> > Nicolas M. Thiéry "Isil" <nth...@users.sf.net <javascript:>>
> > http://Nicolas.Thiery.name/
> >
>
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