Function: rnfeltnorm
Section: number_fields
C-Name: rnfeltnorm
Prototype: GG
Help: rnfeltnorm(rnf,x): returns the relative norm N_{L/K}(x), as an element
 of K.
Doc: $\var{rnf}$ being a relative number field extension $L/K$ as output by
 \kbd{rnfinit} and $x$ being an element of $L$, returns the relative norm
 $N_{L/K}(x)$ as an element of $K$.
 \bprog
 ? K = nfinit(y^2+1); L = rnfinit(K, x^2-y);
 ? rnfeltnorm(L, Mod(x, L.pol))
 %2 = Mod(x, x^2 + Mod(-y, y^2 + 1))
 ? rnfeltnorm(L, 2)
 %3 = 4
 ? rnfeltnorm(L, Mod(x, x^2-y))
 @eprog

