Hi there, On Wed, Sep 01, 2010 at 08:27:22PM -0500, Jason Grout wrote: > On 9/1/10 7:25 PM, David Roe wrote: > > >P.S. To find an example of two parents which currently compare as equal but > >are not the same object, do > >sage: R = Zp(5, print_sep="|") > >sage: S = Zp(5, print_sep=":") > >sage: R == S > >True > >sage: R is S > >False > > > > Carl Witty commented on a similar issue in printing in the RealField > code, and I think he has a very good point. Printing defaults > should not be stored in the parent, but instead should be something > like a module-level option that can be freely set and changed. See > http://trac.sagemath.org/sage_trac/ticket/7682 (except that Trac > doesn't seem to want to display the ticket right now).
Another example: sage: s1 = Set([1,2,3]) sage: s2 = Set([1,2,3]) sage: s1 == s2 True sage: s1 is s2 False Note that sage: s1[0] in s1 True sage: s1[0].parent() Integer Ring So that one can argue that s1 is not a real parent. However: sage: isinstance(s1, Parent) True Cheers, Florent -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
