2022-03-03 23:18:16 +0200 marked best answer Declare diagonal matrix with unknown variables in GF(2). I have an equation of the form $AXB = V$, that I am trying to solve using Sage. All matrixes are in $GF(2)$, $A$ and $X$ are of size 32x32, and $B$ and $V$ column vectors of size 32. My unknown matrix $X$ consists in zeros, except on the diagonal where I'd like to have 32 unknowns (representing each bit of a unknown 32-bits integer). I first tried to declare an array of variables like this:  vars_list = list(var("x_%d" % i) for i in range(32))  which throws me a "TypeError: x_0 is not a variable of Univariate Polynomial Ring in X over Finite Field of size 2 (using GF2X)". Looking at Sage documentation, I didn't find a way to declare them in $GF(2)$. Using this link, I tried to declare my variables like this:  x_1 = SR(GF(2)(1)) * var("x1")  which gave me this time a "TypeError: positive characteristic not allowed in symbolic computations". How should I setup $X$ so I can solve my equation? 2022-03-03 23:18:16 +0200 received badge ● Scholar (source) 2022-03-03 23:18:13 +0200 commented answer Declare diagonal matrix with unknown variables in GF(2). Indeed, it wasn't very complex... Thank you for your help. 2022-03-03 22:45:43 +0200 commented answer Declare diagonal matrix with unknown variables in GF(2). Thank you for the answer and the reference, I'll be sure to check it. A last question if I may: your answer worked fine, 2022-03-03 20:59:01 +0200 received badge ● Editor (source) 2022-03-03 20:59:01 +0200 edited question Declare diagonal matrix with unknown variables in GF(2). Declare diagonal matrix with unknown variables in GF(2). I have an equation of the form $AXB = V$, that I am trying to s 2022-03-03 19:24:52 +0200 asked a question Declare diagonal matrix with unknown variables in GF(2). Declare diagonal matrix with unknown variables in GF(2). I have an equation of the form $AXY = V$, that I am trying to s 2021-11-07 17:14:23 +0200 received badge ● Popular Question (source) 2021-11-06 22:31:21 +0200 commented answer Creating a multivariate polynomial with ideal Perfect, thank you very much for all your help! 2021-11-06 22:31:11 +0200 commented answer Creating a multivariate polynomial with ideal Perfect, thank you very much for your help! 2021-11-05 23:29:23 +0200 commented answer Creating a multivariate polynomial with ideal I guess it is invertible, yes. It is the Q one at the very end of the page 18 here : https://keccak.team/files/Keccak-re 2021-11-05 23:26:03 +0200 commented answer Creating a multivariate polynomial with ideal I guess it is invertible, yes. It is the Q one at the very end of the page 18 here : https://keccak.team/files/Keccak-re 2021-11-05 22:50:02 +0200 received badge ● Supporter (source) 2021-11-05 22:13:26 +0200 commented answer Creating a multivariate polynomial with ideal It gives me a TypeError : self must be an integral domain. Update : I also tried the inverse_of_unit() builtin of a poly 2021-11-05 22:13:09 +0200 commented answer Creating a multivariate polynomial with ideal It gives me a TypeError : self must be an integral domain. Update : I also tried the inverse_of_unit() builtin of a poly 2021-11-05 21:52:42 +0200 commented answer Creating a multivariate polynomial with ideal It gives me a TypeError : self must be an integral domain. 2021-11-05 20:50:09 +0200 commented answer Creating a multivariate polynomial with ideal Thank you, it worked fine. Another question: how could I create a polynomial of the same nature, power -1 ? It tells me 2021-11-05 16:11:11 +0200 commented answer Creating a multivariate polynomial with ideal Thank you, it worked fine. Another question: how could I create a polynomial of the same nature, power -1 ? It tells me 2021-11-05 13:45:06 +0200 received badge ● Student (source) 2021-11-05 01:19:47 +0200 asked a question Creating a multivariate polynomial with ideal Creating a multivariate polynomial with ideal Hello, new user of sage here. I have a computation not too difficult too m