proposition: Lemma orbit_lcoset A a x : orbit to (a *: A) x = orbit to A (to x a).
proof: Proof. by rewrite orbit_lcoset_in ?subsetT ?inE. Qed.
imports: mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat div seq) mathcomp(fintype bigop finset fingroup morphism perm) mathcomp(automorphism quotient)