I want to calculate discriminants using symmetric polynomials. I am working on the quadratic discriminant first. Here is my attempt:
P.<x1,x2>=PolynomialRing(QQ)
S=SymmetricFunctions(P.base_ring())
e = S.elementary()
e(S.from_polynomial((x1-x2)^2))
this produces
e[1, 1] - 4*e[2]
How can I convert this output to b^2 - 4 * a * c?
Thank you