And more precisely a lack of simplification at some point sage: w[0].denominator() 2 sage: z[0].denominator() 4
2014-10-04 19:57 UTC+02:00, Vincent Delecroix <[email protected]>: > Hello Nathann, > > Seems to be the comparison in the number field... > > sage: z[0] > -1/2 > sage: w[0] > -1/2 > sage: z[0] == w[0] > False > sage: z[0].parent() > Number Field in a with defining polynomial x^3 + x - 1 > sage: w[0].parent() > Number Field in a with defining polynomial x^3 + x - 1 > > Vincent > > 2014-10-04 19:44 UTC+02:00, Nathan Dunfield <[email protected]>: >> There's something wrong with comparison operators for elements of >> QuaternionAlgebras defined over a number field. Here's a simple example, >> where first it gives the wrong answer and then, after doing some >> arithmetic >> >> with the elements, a mix of right and wrong answers: >> >> sage: K = NumberField(x**3 + x - 1, 'a') >> sage: D.<i,j,k> = QuaternionAlgebra(K, -1, -3) >> sage: x = (i + j)/K(2) >> sage: z = (-1 + (i + j) + k)/K(2) - x >> sage: w = i * x >> sage: w, z >> (-1/2 + 1/2*k, -1/2 + 1/2*k) >> sage: w == z >> False >> sage: z == w >> False >> sage: z - w >> 0 >> sage: z == w, w == w, z-w == 0 >> (True, True, False) >> >> I looked in trac, but I didn't see this. Is this issue already known, >> and, >> >> if so, is there a simple work-around? >> >> Thanks, >> >> Nathan >> >> -- >> You received this message because you are subscribed to the Google Groups >> "sage-devel" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected]. >> To post to this group, send email to [email protected]. >> Visit this group at http://groups.google.com/group/sage-devel. >> For more options, visit https://groups.google.com/d/optout. >> > -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
