sure, i think it is a bit weird as well. It certainly has behaviour that is unexpected. I think this will cause a lot of confusion, so I think openning a ticket is a good idea.
As for multiplying those two polynomials, it seems that what you have said works. I will give it a try. Cheers On 30 May, 13:16, simon.k...@uni-jena.de wrote: > Hi! > > A little addendum: > > > For a similar reason, neither f nor g are elements of R. > > I would agree that it is a little confusing that something is equal to > an element of a polynomial ring but is not an element of that ring, or > in pure form: > sage: R = QQ['x','y'] > sage: R1.<x>=QQ[] > sage: R2.<y>=QQ[] > sage: x in R > False > sage: x == R.gen(0) > True > > This is at least inconsistent, because for rational numbers that > happen to be integers, the containment is answered in a different way: > sage: (1/1).parent() > Rational Field > sage: (1/1).parent() == ZZ > False > sage: 1/1 in ZZ > True > > So, although 1/1 is given as an element of the rationals, it is > recognized as an element of the integers. > > But why is the generator x of a univariate polynomial ring not > recognized as an element of a bivariate polynomial ring in x and y? > > Question to the developers: Is this perhaps due to the following (a > bug in the coercion system?): > sage: R._has_coerce_map_from(R) > > --------------------------------------------------------------------------- > TypeError Traceback (most recent > call last) > > /home/SimonKing/.sage/temp/sage.math.washington.edu /5548/ > _home_SimonKing__sage_init_sage_0.py in <module>() > > TypeError: 'dict' object is not callable > > This happens on sage.math with sage-3.4.2. Shall I open a ticket? > > Cheers, > Simon --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support-unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
