galoischardet

Function: galoischardet
Section: number_fields
C-Name: galoischardet
Prototype: GGD1,L,
Help: galoischardet(gal, chi, {o=1}): return the determinant character of the
 character chi.
Doc: Let $G$ be the group attached to the \kbd{galoisinit}
 structure~\var{gal}, and
 let $\chi$ be the character of some representation $\rho$ of the group $G$,
 where a polynomial variable is to be interpreted as an $o$-th root of 1.
 For instance, if \kbd{[T,o] = galoischartable(gal)} the characters
 $\chi$ are input as the columns of \kbd{T}.

 Return the degree-$1$ character $\det\rho$ as the list of $\det \rho(g)$,
 where $g$ runs through representatives of the conjugacy classes
 in \kbd{galoisconjclasses(gal)}, with the same ordering.
 \bprog
 ? P = x^5 - x^4 - 5*x^3 + 4*x^2 + 3*x - 1;
 ? polgalois(P)
 %2 = [10, 1, 1, "D(5) = 5:2"]
 ? K = nfsplitting(P);
 ? gal = galoisinit(K);  \\ dihedral of order 10
 ? [T,o] = galoischartable(gal);
 ? chi = T[,1]; \\ trivial character
 ? galoischardet(gal, chi, o)
 %7 = [1, 1, 1, 1]~
 ? [galoischardet(gal, T[,i], o) | i <- [1..#T]] \\ all characters
 %8 = [[1, 1, 1, 1]~, [1, 1, -1, 1]~, [1, 1, -1, 1]~, [1, 1, -1, 1]~]
 @eprog