(** ** Results about [of_nat] and [of_succ_nat] *)

(* Specifications: *)
Lemma of_nat_succ (n:nat) : of_succ_nat n = of_nat (S n).
Lemma pred_of_succ_nat (n:nat) : pred (of_succ_nat n) = of_nat n.
Lemma succ_of_nat (n:nat) : n<>O -> succ (of_nat n) = of_succ_nat n.
Inductive SqrtSpec : positive*mask -> positive -> Prop :=
| SqrtExact s x : x=s*s -> SqrtSpec (s,IsNul) x
| SqrtApprox s r x : x=s*s+r -> r <= s~0 -> SqrtSpec (s,IsPos r) x.