Section NormalComplement.
Variables K H G : {group gT}.
Hypothesis complH_K : H \in [complements to K in G].
End NormalComplement.
(* Semi-direct product *)

Lemma quotient_sdprodr_isom G A B M :
A ><| B = G -> M <| B ->
{f : {morphism B / M >-> coset_of (A <*> M)} |
isom (B / M) (G / (A <*> M)) f
& forall L, L \subset B -> f @* (L / M) = A <*> L / (A <*> M)}.