The <> notation creates Python variables of the same name, so you shouldn't use it together with the PolynomialRing(..., "e") constructor. Basically, you need to be aware that the the string label "a" can be attached to multiple Python variable names (its OK to do so for the computer but you will get confused):
sage: p.parent() Multivariate Polynomial Ring in a, b, c, d, e over Multivariate Polynomial Ring in a, b, c, d over Rational Field sage: preparse("R.<a,b,c,d,e> = PolynomialRing(PolynomialRing(QQ,'a,b,c,d'),'e',sparse=True)") "R = PolynomialRing(PolynomialRing(QQ,'a,b,c,d'),'e',sparse=True, names=('a', 'b', 'c', 'd', 'e',)); (a, b, c, d, e,) = R._first_ngens(5)" As for the second part, searching solutions over floating-point numbers should be avoided. You probably want to first figure out if your system is over/underdetermined and compute a lexicographic order Groebner basis: http://ask.sagemath.org/question/403/method-for-solving-a-large-system-of-under -- You received this message because you are subscribed to the Google Groups "sage-support" group. To post to this group, send email to sage-support@googlegroups.com. To unsubscribe from this group, send email to sage-support+unsubscr...@googlegroups.com. Visit this group at http://groups.google.com/group/sage-support?hl=en.