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

Lemma sdprod_recr n G K H H1 :
#|G| <= n -> K ><| H = G -> H1 \proper H ->
exists G1 : {group gT}, [/\ #|G1| < n, G1 \subset G & K ><| H1 = G1].