proposition: Lemma class_support_norm A G : G \subset 'N(class_support A G).
proof: Proof. by apply/normsP; apply: class_supportGidr. Qed.
imports: HB(structures) mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq choice) mathcomp(fintype div path tuple bigop prime finset)