Hi Niles, On 28 Nov., 23:49, Niles <nil...@gmail.com> wrote: > I've noticed the following strange behavior (bug): > > sage: A.<a> = PolynomialRing(QQ) > sage: 3 in A > True > > sage: A2.<a,b> = PolynomialRing(QQ) > sage: 3 in A2 > False > > So apparently "in" for multivariate polynomial rings is slightly > broken, but I don't know where to look to fix it. I did spend some > time looking for documentation or previous email threads, but "in" > makes for a tough search.
I remember that someone has explained to me that membership testing is specified in Sage as e in P <=> e==P(e) where e==P(e) means in particular that no error is raised. However, as your example demonstrates, that specification is not always used. IIRC, this default implementation of the __contains__ could be inherited from the class sage.structure.parent.Parent Cheers, Simon -- 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
