proposition: Lemma cm_unit_unique_rht : forall x : M, is_rht_unit csg_op x -> x [=] [0].
proof: Proof. intros x h. red in h. Step_final ([0][+]x). Qed.
imports: Coq.Arith.Euclid CoRN.model.Zmod.Cmod CoRN.algebra.CSemiGroups CoRN.tactics.csetoid_rewrite CoRN.model.structures.Nsec CoRN.util.SetoidPermutation Coq.Setoids.Setoid Coq.Classes.Morphisms