William, In SAGE 2.8 it seems there is a problem with the is_principal method for fractional ideals in a number field. In the code below I create the same ideal in two different ways and obtain two different answers from is_principal (True and False).
K = QuadraticField(-119,'a') P2 = K.ideal([2]).factor()[0][0] I = P2^5 a = K.0 J = K.ideal([1/2*a+3/2]) I==J I.is_principal() J.is_principal() I believe the problem is with the following line in the is_principal() method: if len (self.gens()) <= 1: Instead it should read: if len (self.gens_reduced()) <= 1: Not 100% sure, but I thought I would bring it to your attention. - Kevin --~--~---------~--~----~------------~-------~--~----~ 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-forum URLs: http://sage.math.washington.edu/sage/ and http://sage.scipy.org/sage/ -~----------~----~----~----~------~----~------~--~---
