Hi Nicolas, On 2013-02-25, Nicolas M. Thiery <nicolas.thi...@u-psud.fr> wrote: > It was a design decision that the user could create his "own" free > module by specifying a prefix, even if the base ring and index set is > the same. So the result for ``G is y`` is as desired. > > On the other hand, I personally consider that ``G == y`` is buggy: it > should return False; the user explicitly asked for G and y to be > distinct even if they are trivially isomorphic. > > Different opinion anyone? > > My bet is that our code does not depend on ``G==y`` returning True.
In a preliminary and rather intrusive version of a fast UniqueRepresentation, I *forced* comparison by identity---hence, it became impossible to create a non-unique parent inheriting from UniqueRepresentation. But the result were numerous doctest errors in sage/combinat, and they only disappeared whan I made CombinatorialFreeModule a CachedRepresentation (not UniqueRepresentation) and used UniqueRepresentation only on the classes that inherit from CombinatorialFreeModule. > So fixing it should cause no nontrivial issue (except for a potential > little annoyance for users who got used to this "feature"). And it > would make CombinatorialFreeModule not deviate from the specs of > UniqueRepresentation and solve your issue cleanly. Well, using CachedRepresentation for CombinatorialFreeModule and UniqueRepresentation for all sub-classes *is* clean, I think. Unless you way that the "unique parent condition" is a law and not a rule of thumb. Cheers, Simon -- You received this message because you are subscribed to the Google Groups "sage-combinat-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-combinat-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-combinat-devel@googlegroups.com. Visit this group at http://groups.google.com/group/sage-combinat-devel?hl=en. For more options, visit https://groups.google.com/groups/opt_out.
