proposition: Lemma Clifford_astab1 (W : sH) : 'C[W | 'Cl] = rstabs rG W.
proof: Proof. apply/setP=> x /[!inE]; apply: andb_id2l => Gx. rewrite sub1set inE (sameP eqP socleP) !val_Clifford_act //. rewrite andb_idr // => sWxW; rewrite -mxrank_leqif_sup //. by rewrite mxrankMfree ?repr_mx_free. Qed.
imports: HB(structures) mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq path) mathcomp(div choice fintype tuple finfun bigop prime) mathcomp(ssralg poly polydiv finset fingroup morphism) mathcomp(perm automorphism quotient finalg action zmodp) mathcomp(commutator cyclic center pgroup matrix mxalgebra) mathcomp(mxpoly)