proposition: Theorem binds_singles : forall A x y (v w : A) ys (ws : list A), x = y -> v = w -> x ∹ v ⋲ (y :: ys ∷ w :: ws).
proof: Proof. intros A x y v w ys ws Heq1 Heq2. rewrite Heq1, Heq2. unfold binds. rewrite singles_cons. apply get_concat_r; auto. Qed.
imports: Utf8 Equalities CoreGenericEnv