Taking gcd with respect to one variable
I want to compute gcdX((X−y)2−a,Xq−12−1) with respect to X(taking y as a field constant).
I can't see any direct implementation of this in sage. Can any one suggest how to implement it.
Here Arithmetic is over GF(p) and y is root of cyclotomic polynomial of degree r over GF(p) and q=pr
One can choose 'a' to be any quadratic residue modulo p
I tested what I think should be the standard way of doing this computation in Sage. Unfortunately, an implementation is lacking, and it does not work: