Section Properties.
Implicit Types x y : TVar.
Implicit Types xs ys : list TVar.
(* ---------------------------------------------------------------------- *)
(** *** Primary properties *)
(* ---------------------------------------------------------------------- *)
(** **** Properties of singulars *)

Axiom singles_cons : forall A x xs (v : A) (vs : list A),
(x :: xs) ∷ (v :: vs) = (xs ∷ vs) & (x ∶ v).