On Nov 2, 2006, at 11:02 PM, Robert Bradshaw wrote:
> I think if there is a natural coercion S -> R, one should also be > able to do > > x * y = x * y.base_extend(R) > > Right now something like > > sage: R.<x> = ZZ['x'] > sage: (1/2) * (x^2-x) > > throws an "unable to find a common parent" type error. I am wondering > if there are any (many) other cases where there is an unambiguous > common parent that is not the parent of either "sibling." I think > there should be generic code able to handle this for elements defined > over a basering (e.g. polynomials, series, matrices, etc.) but > perhaps there are other such situations too (e.g. the product of > elements of two extensions of Q, though I haven't given thought to > how messy this could become). This is much harder. I agree it would be nice, but how would you handle something like sage: R.<x> = ZZ["x"] sage: S.<y> = ZZ["y"] sage: x*y ?? David --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-devel@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-devel URLs: http://sage.scipy.org/sage/ and http://modular.math.washington.edu/sage/ -~----------~----~----~----~------~----~------~--~---
