proposition: Lemma dprodWsd A B G : A \x B = G -> A ><| B = G.
proof: Proof. by move=> defG; have [_ _ /dprodEsd <-] := dprodP defG. Qed.
imports: HB(structures) mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq div) mathcomp(choice fintype bigop finset fingroup morphism) mathcomp(quotient action)