Canonical sdprod_baseFinGroupType :=
Eval hnf in BaseFinGroupType sdT sdprod_groupMixin.
Canonical sdprod_groupType := FinGroupType sdprod_mulVg.
Definition sdpair1 x := insubd sdprod_one (1, x) : sdT.
Definition sdpair2 a := insubd sdprod_one (a, 1) : sdT.

Lemma sdpair1_morphM : {in R &, {morph sdpair1 : x y / x * y}}.