On 2/8/07, William Stein <[EMAIL PROTECTED]> wrote: > Didier, > > Would RealLib, which still hasn't fully made its way into SAGE, be very > relevant > to this question? Can it somehow decide equality of some class of real > numbers > defined via an algorithm (e.g., sqrt(2) + 1 - 1 is defined by an > algorithm...)? > Anyway, if RealLib is relevant, could you say something about that?
Unfortunately, no. Reallib has strict comparisons, but equality tests will loop indefinitely. From the documentation: "The equality test is undecidable, i.e. no function can exist that can always give a positive answer when two numbers are equal and not complete or give a negative answer if they are not. The system does not provide this test, nor the non-strict inequalities which, without the possibility to recognize equality, coincide with their strict counterparts." didier --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to [email protected] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-support URLs: http://sage.math.washington.edu/sage/ and http://sage.scipy.org/sage/ -~----------~----~----~----~------~----~------~--~---
