On Sat, 28 Oct 2006 19:20:31 -0700, David Harvey <[EMAIL PROTECTED]> wrote:
> > > On Oct 28, 2006, at 10:05 PM, William Stein wrote: > >> Regarding ring and algebra elements, suppose x is in a ring R and y >> is in a K-algebra S. We want to define what "x * y" means. The >> most natural thing to me would be >> >> x * y is K._coerce_(x) * y >> >> and that's it. If no coerce map exists, fail. >> >> Am I missing something? The above rule is definitely easy to >> understand. > > What if you multiply two CommutativeAlgebraElements? You could either > attempt the base extension from your previous email, or you could try > "forgetting" that the guy on the left is a commutative algebra > element, only treat it as a ringElement, and try the coercion you > wrote down just above. Could these be different? They could be different so we fix a convention. I think the best is to always stay in the same category, so I think we should attempt to do arithmetic with commalgelts. If (and only if) that fails, would we try the other suggestion you make (maybe). William --~--~---------~--~----~------------~-------~--~----~ 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/ -~----------~----~----~----~------~----~------~--~---
