On Jan 25, 2008 3:36 AM, Robert Bradshaw <[EMAIL PROTECTED]> wrote:
>
> I agree--rather than just having a signed/unsigned infinity ring, I
> think there should be an extended ring for Z, Q, R, C--both signed
> and unsigned when there is an absolute order. When does the concept
> of infinity make sense for a given ring? 1 (or 2)-point
> compactification? (not for Q), ordering (not for C), maybe an
> unbounded valuation (making "p-adic infinity" equal to zero?)
>
> Implementation-wise, this could be accomplished via a generic wrapper
> around the rings and their elements (which I think could still be
> quite fast, and coercion would be natural and efficient too, not to
> mention the difficulties and inefficiencies raised by having multiple
> types for a single parent, or Integers with non-integer-ring parents).
>
> The default sage oo would be +Infinity in Z \union {\pm \infty}.
>Yes, this sounds good. I -- then David Roe -- didn't implement something like the above I think only because we didn't need it for our applications (to modular symbols and p-adics). But I could certainly see how it would be very useful for more general applications. 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://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
