On 05/05/15 11:00, Nicolas M. Thiery wrote: > On Tue, May 05, 2015 at 10:41:42AM +0200, Jeroen Demeyer wrote: >> what are the types CategoryObject and Parent supposed to represent? For >> example, I don't understand why generators and names are dealt with on the >> level of CategoryObject but constructing elements is dealt with on the level >> of Parent. >> In fact, in all of Sage, there is only a single class which is a >> CategoryObject but not a Parent: >> >> class SimplicialComplex(CategoryObject, GenericCellComplex) > > Parents are supposed to model sets (typically with some structure), > when CategoryObject can be more general. Simplicial complexes are > typical examples, where we want to model instead a collection of sets > with some structure. This feature has indeed not been used much yet > (which also reflects in the fact that almost all categories are > subcategories of `Sets()` rather than of `Objects()`). > > Very much like for Parent, there probably are things that are in > CategoryObject for very old legacy reasons (typically pre-categories!) > and really do not belong there; this could typically be the case for > generators and names.
IMHO, they do not belong either to parents. A set has generators? sage: Partitions(5).gens_dict() Traceback (most recent call last): ... AttributeError: 'StandardPermutations_n_with_category' object has no attribute 'gens'AttributeError: 'Partitions_n_with_category' 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/d/optout.
