Lemma isog_set1X (H2 : {group gT2}) : isog H2 (setX 1 H2).
Proof.Proof.
move=> H1_1 H2_1; apply/eqP.oup rT}).Inductive sdprod_by (to : groupAction D R) : predArgTypeCoercion pair_of_sd to (u : sdprod_by to) := ltion sdval := (@pair_of_sd to).

Canonical sdprod_subType := Eval hnf in [subType for sdvalnical sdprod_subCountType := Eval hnf in [subCountType of sdT].
Definition sdprod_finMixin := [finMixin of sdT by <:].
Canonical sdprod_finType := FinType sdT sdprod_finMixin.

Proof.