polynomials over integers modulo...
Just wanted to report a bug: it's impossible to work with polynomials with coefficients in Z/n, at least for n= 2^64:
kk= Zmod(2^64)
n= 2
R= PolynomialRing(kk, [ "x" + str(i+1) for i in range(n) ])
P= R.random_element()
This fails. More generally it's impossible to multiply an element of kk by a generator of R. This is sage 10.6.
PS from the message error it's clear that a certain "long" integer in the code should be "unsigned long" instead.