proposition: Lemma dom_cond_in : r ⨾ ⦗d'⦘ ⊆ ⦗d⦘ ⨾ r' -> d' ⊆₁ dom_cond r d.
proof: Proof. unfold dom_cond; unfolder; ins; desf. splits; eauto; eapply H; eauto. Qed.
imports: HahnBase HahnSets HahnRelationsBasic HahnEquational HahnRewrite Setoid