2021-06-16 22:40:45 +0100 received badge ● Famous Question (source) 2019-04-23 09:42:01 +0100 received badge ● Notable Question (source) 2019-04-22 13:58:59 +0100 received badge ● Student (source) 2017-10-16 16:28:24 +0100 received badge ● Popular Question (source) 2015-10-02 01:55:04 +0100 asked a question Multivariate Laurent series I'm trying to perform calculations with two variables $z, u$, one of which, $z$, should be invertible. Apparently Laurent series rings are not yet implemented for multivariate rings. I tried the following R = QQ[['zed, you, zedi']] R Multivariate Power Series Ring in zed, you, zedi over Rational Field x = R.gens() x (zed, you, zedi) i = x[0]*x[2] - 1 i -1 + zed*zedi I = i*R I S = QuotientRing(R, I, names="z, u, xi") S Principal ideal (-1 + zed*zedi) of Multivariate Power Series Ring in zed, you, zedi over Rational Field Quotient of Multivariate Power Series Ring in zed, you, zedi over Rational Field by the ideal (-1 + zed*zedi) g = S.gens() g (zed, you, zedi) g[0]*g[2] zed*zedi  Apparently, in the quotient ring I still get that $z z^{-1}$ doesn't simplify to 1. Also, my assigned names aren't recognized. What am I doing wrong? Is this even the best way of dealing with multivariate Laurent polynomials? Thank you. (This is my first day using sage and my first question here on ask.sagemath.org. Please let me know if I've done something wrong.)