On Tue, Sep 22, 2009 at 11:25:12AM -0700, Robert Bradshaw wrote:
> On Sep 22, 2009, at 4:49 AM, Nicolas M. Thiery wrote:
> > Variant:
> >
> > sage: R = Zmod(6)
> > sage: R.set_category(Fields()) # or maybe better R.add_category
> > (Fields())
> > sage: R in Fields()
> > True
> > sage: assert R in Fields()
> >
> > This avoids cluttering each sage object with an is_bla method which
> > might refer to a completely unrelated category bla. Also, this handles
> > automatically the inheritance of category (so that stating that R is
> > in Fields imposes that it also is a division ring, ...).
>
> One issue with that is that, forever after in your sage session, Zmod
> (6) will be a field (unless you change it manually back, if you know
> that the library function you called changed it...) That's why I
> liked the new object method. Alternatively, this might be a good use
> for contexts.
Good point. I am not very keen on adding new categories on the fly
either. Then, I would vote for R = Zmod(6, category = Fields()), since
many parents readily support this features.
Cheers,
Nicolas
--
Nicolas M. Thiéry "Isil" <nthi...@users.sf.net>
http://Nicolas.Thiery.name/
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