Mike is correct about your first question: your confusion is between coercion maps and conversion maps.
The function you're looking for is _mpoly_base_ring, which is written in sage.rings.polynomial.multi_polynomial_ring_generic.pyx David On Wed, Feb 16, 2011 at 13:06, mmarco <mma...@unizar.es> wrote: > I already new all that, but my question would be: "why > S.has_coerce_map_from(R) returns False?" > > And the second question is "is there a command (or an easy way to > implement it) to recover QQ[x,y,z] from QQ[x][y][z] or any other > similar situation?" > > I know how to deal with these cases by hand, but i am trying to write > a patch for computing discriminants, and there i need a way to > automatically do it. I think i could construct such a function if i > knew how to recognize if a given ring is a polynomial ring or not. > > -- > 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 > -- 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
