Canonical action := Action actP.Definition groupAction := GroupAction gactP.Fact gtype_key : unit.Definition gtype := locked_with gtype_key (sdprod_groupType groupAction).Notation "''D^' n * 'Q'" := (Pextraspecial.ngtypeQ n) : type_scope.Local Notation gtype := Pextraspecial.gtype.Local Notation actp := (Pextraspecial.groupAction p).

Lemma DnQ_extraspecial n : extraspecial 'D^n*Q.