On Thu, Jan 12, 2012 at 05:31:13PM -0800, Travis Scrimshaw wrote:
> > A note, just to be pedantic: Singleton is a special case of
> > UniqueRepresentation (when there are no arguments). And by the way,
> > there is an upcoming Singleton class for that special case coming in
> > #11900.
>
> Good to know. I just wanted to make sure my terminology was
> understood.
Yup. I definitely support circulating the names of standard design
patterns on this list. Ah, and I must take just a bit back my claim:
#11900 implements Category_singleton. The extraction of a super class
Singleton still remains to be done (thought that should be trivial;
mostly a question of documenting it properly).
> > Isn't that the (misnamed) CombinatorialFreeModule?
>
> Yes it is. So there is the object, but no morphism between them?
At this point, it is possible to define morphisms (see
module_morphism), but only as functions, not matrices. The historical
reason why we focused on functions is that, so far, we mostly needed
to implement morphisms between infinite dimensional / large vector
spaces, or by providing the code of the morphism. That being said, in
MuPAD-Combinat, I had started implementing the appropriate matrices,
precisely for the root system code. See
lib/DOMAINS/DOMAIN/IndexedMatrix.mu in the Combinat sources.
Cheers,
Nicolas
--
Nicolas M. Thiéry "Isil" <nthi...@users.sf.net>
http://Nicolas.Thiery.name/
--
You received this message because you are subscribed to the Google Groups
"sage-combinat-devel" group.
To post to this group, send email to sage-combinat-devel@googlegroups.com.
To unsubscribe from this group, send email to
sage-combinat-devel+unsubscr...@googlegroups.com.
For more options, visit this group at
http://groups.google.com/group/sage-combinat-devel?hl=en.
