proposition: Theorem eqrZSym : symmetric rZ eqRz.
proof: Proof. red in |- *; intros a b; case a; case b; simpl in |- *; auto with stalmarck. Qed.
imports: Stalmarck(sTactic) Coq(Relation_Definitions) Coq(ZArith) Coq(Inverse_Image) Coq(Inclusion) Coq(Wf_nat) Coq(List)