Some new GP features
poltomonic
poltomonic(P) return a monic, integral polynomial U such
that U(x) = CT(x/L) for some C, L ∈ Q.
? poltomonic(9*x^2 - 1/2)
%86 = x^2 - 2
? U = poltomonic(9*x^2 - 1/2, &L)
%87 = x^2 - 2
? L
%88 = 6
? U / subst(9*x^2 - 1/2, x, x/L)
%89 = 4