ewrite !repr_mxM // tprodE.
Qed.etG ?oZ // setIC meet_Ohm1 // meet_center_nil ?cfker_normal //.
by rewrite -subG1 not_ffulG.
Qed.ewrite groupJr // !repr_mxM ?groupM ?groupV // mxtrace_mulC repr_mxK.
Qed.

Lemma cfRepr_dadd rG1 rG2 :