On Mon, Mar 21, 2011 at 10:35:55PM +0100, Nicolas M. Thiery wrote: > On Sat, Mar 19, 2011 at 07:37:25AM -0700, Daniel Bump wrote: > > Well, what you are suggesting is a little tricky. Two > > rings will be created at the same time, and the > > multiplication will be implemented by coercing from > > the WeylCharacterRing to the WeightRing, multiplying, > > and coercing back. > > Why tricky?
Well, yes, there is one tricky point with the current organization of the code, where first the WeylCharacterRing is defined, and then the WeightRing is constructed from it. Then of course it's a bit inconvenient to define the product of the former from that of the latter. But that would be easy to change internaly, even without changing the current interface. And then one could use the generic ambient/lift/retract mechanism for subquotients. > Thanks! I'll have a look now. I just pushed my changes on the Sage-Combinat queue. The code uses standard coercion now. In the process, I have factored out a couple functions to the ambient space (from_vector_notation, the coerce_E6 and friends). It's not polished (see the TODO's) but all test pass. I have left for the record the construction of the partial morphism from the WeightRing to the WeylCharacterRing even if it is not currently registered as a conversion (I had a little glitch there, and it's time to go to bed). Even if not registered as a conversion; that could be a useful function for the user, so you may want to keep it and document it. I won't touch the thing tomorrow, so feel free to fold all the 7922 patches together for a better overview. Cheers, Nicolas -- Nicolas M. ThiƩry "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.