What did you put in J ? in fact, the following already produces the bug (sorry for not trying earlier, i thought i did try and there was no bug... must have changed a little something):
sage: k= CyclotomicField(3, "w") sage: A= PolynomialRing(k, ["y9", "y12", "y13", "y15"]) sage: y9, y12, y13, y15= A.gens() sage: J= [ y9 + y12]*A; J.groebner_basis() sage: J.reduce(y9 - y12) -2*y12 sage: J.reduce(y13*y15) y13*y15 sage: J.reduce(y13*y15 + y9 - y12) y13*y15 + y9 - y12 Which is odd. I had read J.reduce?, it seems to indicate that the function returns what i would also call the reduction, but that is linear. So I think this is a bug. On Sep 16, 12:33 pm, Martin Albrecht <[EMAIL PROTECTED]> wrote: > > that's what i expect from the term 'reduction' anyway > > reduce is defined as: > > Reduce an element modulo the reduced Groebner basis for this > ideal. This returns 0 if and only if the element is in this > ideal. In any case, this reduction is unique up to monomial > orders. > > See J.reduce? > > > So if this is a bug i'll give you more details. > > From what you've provided it is hard to tell. Could you provide a small > reproducible example? I know you said its hard to do but without it, it will > be difficult to help you. > > Here are my attempts: > > sage: P.<y9,y12,y13,y15> = PolynomialRing(CyclotomicField(3)) > sage: J.reduce(y13 + y9 - y12) > (-2)*y12 + y13 > sage: J.reduce(y13*y15 + y9 - y12) > y13*y15 + (-2)*y12 > sage: J.reduce(y9 - y12) > (-2)*y12 > > Cheers, > Martin > > -- > name: Martin Albrecht > _pgp:http://pgp.mit.edu:11371/pks/lookup?op=get&search=0x8EF0DC99 > _www:http://www.informatik.uni-bremen.de/~malb > _jab: [EMAIL PROTECTED] --~--~---------~--~----~------------~-------~--~----~ 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://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
