> > I don't know at all the topic of FindStatMap, but it seems that you have > touched > a limitation of Sage's Parent/Element scheme: an object cannot be both a > Parent > and an Element (of another Parent)... This of course contrasts with > Set/Element in > mathematics. >
OK. But maybe that's asking the wrong question anyway. Let me try to abstract things: I have a category and I want to model both objects and morphisms of this category. The objects are modelled as instances of a class "C", with parent being the class "Cs". How do I model the morphisms? The only thing that would be nice to have is composition. By contrast it is (at least currently) not possible to "call" a morphism - think of the objects in the category as labels, and likewise the morphisms should not carry more information than their name, domain and codomain. As a concrete example, let's say that the objects are a, b and c, and I have the set of morphisms generated by m1: a -> b, m2: b -> c and m3: c -> c it would be nice to be able to write m2*m1, and the output should be m2 o m1 etc. The sage class Homset is not really what I want, because it assumes that I can apply a morphism to an element of an object. Thanks for helping! Martin -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
