I believe I understood now: sage: ?parent Type: function <snip> Return x.parent() if defined, or type(x) if not.
I wonder why this is a function, and not a method of Parent? (Am I right that all Sage parents inherit from Parent? Would be great to know this) Set_object inherits from Set_generic, and does not define a parent method, for whatever reason, maybe because the elements of the set need not have a common type. I just saw on http://trac.sagemath.org/sage_trac/attachment/ticket/2314/coerce_2_sets.patch a patch to primes.py, which, in particular, makes Primes inherit from a new class Subset instead of Set_generic. I guess this adresses the issue. It would be wonderful to hear either of "yes, correct", or "no, you are mistaken". Many thanks, Martin --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-support URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---