proposition: Lemma neq0_has_constt (phi : 'CF(G)) : phi != 0 -> exists i, i \in irr_constt phi.
proof: Proof. move=> nz_phi; apply/existsP; apply: contra nz_phi => /pred0P phi0. by rewrite [phi]cfun_sum_constt big_pred0. Qed.
imports: HB(structures) mathcomp(ssreflect ssrbool ssrfun eqtype choice ssrnat seq) mathcomp(path div fintype tuple finfun bigop prime order) mathcomp(ssralg poly finset gproduct fingroup morphism) mathcomp(perm automorphism quotient finalg action zmodp) mathcomp(commutator cyclic center pgroup nilpotent sylow) mathcomp(abelian matrix mxalgebra mxpoly mxrepresentation) mathcomp(vector ssrnum algC classfun archimedean)