I'm trying to work with a quotingring of a matrix space. Now I use the following code. But since $n$ is my modulus I expect my second matrix to be equal to $M_1$ in this quotient ring. But it's like its just ignoring the fact that its a quotient ring and it does every computation in MS. What am I doing wrong or is my understanding of quotient rings flawed?
Thanks in advance.
MS = MatrixSpace(ZZ,2,2)
n=MS([[17,19],[11,31]])
R = MS.quotient_ring(MS*n*MS) #or R = MS.quotient_ring(n)
M1 = R([[1,1],[1,1]])
print(M1)
M2 = R(n+M1.lift())
print(M2)