Hi, I do like the project find_stat but do not like the way it intends to do it. In that sense, I mostly agree with Nathann objections.
Following Thierry, why combinatorial maps are not implemented as morphisms between two proper parents ? We could add some semantic to morphisms (injectivity/surjectivity/bijectivity, ...) which is definitely useful. Note that some semantic is already there as a morphism might be a map between sets or a map between between graded objects. It is possible to implement a decorator that actually creates a morphism from a method (@morphism_from_method) and cache it somewhere. I think that it should not transform a method to a combinatorial map (which was one of the main Nathann's objection) but it might be useful that such decorator exists. Then, the problem is what method is not an actual morphism between two parents (do we want decorators everywhere) ? Where do we register the morphisms (in the parent, in a database) ? Another problem is that given a parent, it is not possible to determine all the morphisms from or to that parent ("possible" here means that such function will never exists, because most of the objects and morphisms are dynamically created with the coercion framework and that set of morphisms is potentially infinite). Nevertheless, coercion framework takes care about somewhat "natural" morphisms and combinatorial maps are somewhat opposite (ie non trivial transformations). But still, some semantic might be applied to coercion morphisms. There are several obstruction to such project: - an object (let say the partition [3,2,1]) may have several parent (Partitions of 6, Partitions graded by the length, ...) but the combinatorial map exists somewhat independently of the parent - we need to convince Nathann that it would be good to have the parent Graphs ;-) Best Vincent -- 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 sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at http://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/groups/opt_out.