Hi Mark, On 20 Apr., 08:35, msh...@math.vt.edu wrote: > sage: ZA=ZZ.algebra(QQ,category=CommutativeAdditiveGroups()) > > This creates the group algebra of the group (ZZ, +) with > rational coefficients. The construction sounds functorial to me, > at least on objects. But it doesn't seem to have an accompanying > way to work with morphisms.
Sure. That's a *method* relying on a mathematical functor. But it is not a functor in the sense of Sage construction functor. In fact, a construction functor is missing in this case: sage: ZA=ZZ.algebra(QQ,category=CommutativeAdditiveGroups()) sage: print ZA.construction() None Cheers, Simon -- 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.