Function: galoisfixedfield
Section: number_fields
C-Name: galoisfixedfield
Prototype: GGD0,L,Dn
Help: galoisfixedfield(gal,perm,{flag},{v=y}): gal being a galois field as
 output by galoisinit and perm an element of gal.group or a vector of such
 elements, return [P,x] such that P is a polynomial defining the fixed field
 of gal[1] by the subgroup generated by perm, and x is a root of P in gal
 expressed as a polmod in gal.pol. If flag is 1 return only P. If flag is 2
 return [P,x,F] where F is the factorization of gal.pol over the field
 defined by P, where the variable v stands for a root of P
Description: 
 (gen, gen, ?small, ?var):vec	galoisfixedfield($1, $2, $3, $4)

