The reason I put it in is that if you have signed infinities then you might as well preserve the sign when you invert them, which means that you should have a divider. Yes, that means you sometimes get elements where you don't know if it's positive or negative. I think that's okay, but then I'm the one that originally made the design decision, so.... David
On Jan 17, 2008 9:52 AM, David Harvey <[EMAIL PROTECTED]> wrote: > > Hi folks (especially william + robert + david roe), > > I showed up for Doc Days 1 and started looking at the infinity and > extended integer ring stuff. > > Question: why does the "unsigned infinity ring" not have a zero > element, whereas the "(signed) infinity ring" has a zero? > > This is okay: > > sage: 0 / Infinity > Zero > > But this is way confusing: > > sage: oo = UnsignedInfinityRing(Infinity) > sage: 0 / oo > A number less than infinity > > I totally expected the last output to be Zero. But it can't be, > because the UnsignedInfinityRing doesn't have a zero element. > > On the other hand, if there's a zero element, then you start having > issues with things like > > sage: UnsignedInfinityRing(2) - UnsignedInfinityRing(3) > > because you can't tell if it's zero or not. > > Thoughts? > > 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/ -~----------~----~----~----~------~----~------~--~---
