proposition: Lemma cfRepr_sign : cfRepr sign_repr = sign_char.
proof: Proof. apply cfunP => /= s; rewrite /= !cfunE inE /= !mulr1n. rewrite /trmx trace_mx11 /sign_mx. by case: (odd_perm s) => /=; rewrite ?expr1 ?expr0 !mxE eqxx. Qed.
imports: mathcomp(all_ssreflect) mathcomp(fingroup perm ssralg morphism perm action) mathcomp(zmodp) mathcomp(vector matrix mxalgebra ssrnum algC) mathcomp(mxrepresentation classfun character) permcomp tools partition congr cycles cycletype presentSn