proposition: Lemma set_equiv_min_elt (S: r ≡ r') : min_elt r ≡₁ min_elt r'.
proof: Proof. unfold min_elt, same_relation, set_equiv, set_subset in *; intuition; eauto. Qed.
imports: HahnBase HahnList HahnSets HahnRelationsBasic HahnEquational HahnRewrite HahnMaxElt Arith Setoid