(** ** Remaining constants not defined in Stdlib.Init.Nat *)
(** NB: Aliasing [le] is mandatory, since only a Definition can implement an interface Parameter... *)
Definition eq := @Logic.eq nat.
Definition le := Peano.le.
Definition lt := Peano.lt.
(** ** Basic specifications : pred add sub mul *)

Lemma log2_spec n : 0<n ->
2^(log2 n) <= n < 2^(S (log2 n)).