Function: rnfeltabstorel
Section: number_fields
C-Name: rnfeltabstorel
Prototype: GG
Help: rnfeltabstorel(rnf,x): transforms the element x from absolute to
 relative representation.
Doc: $\var{rnf}$ being a relative
 number field extension $L/K$ as output by \kbd{rnfinit} and $x$ being an
 element of $L$ expressed as a polynomial modulo the absolute equation
 \kbd{\var{rnf}.pol}, computes $x$ as an element of the relative extension
 $L/K$ as a polmod with polmod coefficients.
 \bprog
 ? K = nfinit(y^2+1); L = rnfinit(K, x^2-y);
 ? L.pol
 %2 = x^4 + 1
 ? rnfeltabstorel(L, Mod(x, L.pol))
 %3 = Mod(x, x^2 + Mod(-y, y^2 + 1))
 ? rnfeltabstorel(L, Mod(2, L.pol))
 %4 = 2
 ? rnfeltabstorel(L, Mod(x, x^2-y))
  ***   at top-level: rnfeltabstorel(L,Mod
  ***                 ^--------------------
  *** rnfeltabstorel: inconsistent moduli in rnfeltabstorel: x^2-y != x^4+1
 @eprog

