Section InternalProd.
Variable gT : finGroupType.
Implicit Types A B C : {set gT}.
Implicit Types G H K L M : {group gT}.
Local Notation pprod := (partial_product gT).
Local Notation sdprod := (semidirect_product gT) (only parsing).
Local Notation cprod := (central_product gT) (only parsing).
Local Notation dprod := (direct_product gT) (only parsing).

Lemma mul0g : left_zero (@set0 gT) mulg.