proposition: Lemma restr_eq_union A r r' B (f : A -> B) : restr_eq_rel f (r ∪ r') ≡ restr_eq_rel f r ∪ restr_eq_rel f r'.
proof: Proof. u. Qed.
imports: Program.Basics Arith micromega.Lia Permutation List Setoid HahnBase HahnList HahnRelationsBasic HahnSets