proposition: Lemma cardG_gt0 : 0 < #|G|.
proof: Proof. by rewrite lt0n; apply/existsP; exists (1 : gT). Qed.
imports: HB(structures) mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq choice) mathcomp(fintype div path tuple bigop prime finset)