Hello, I think I stumbled across a bug in groebner_basis(). The example below doesn't generate the unique reduced Groebner basis of the ideal generated by f and g, but instead the set
[y^3 + 2*y^2 - x - y, x^2 + 2*y, x*y - y^2 + 1] is returned. This set isn't a Groebner basis at all. The correct basis should be [1 - 2*y^2 + 2*y^3 + y^4, x + y - 2*y^2 - y^3] . Here is the code: R.<x,y> = PolynomialRing(QQ, 'lex') f = x^2 + 2*y g = x*y - y^2 + 1 I = ideal([f,g]) print I.groebner_basis() I tested it with version 6.7, 8.0.rc1 and on sagecell.sagemath.org and with different algorithms as argument to groebner_basis(), the result is always the same. Is this a bug, or do I have some stupid error in my code? Regards, Johannes -- 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 sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at https://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
