Module MyNat.
End MyNat.
Open Scope R_scope.
(** * Integers *)
(** Integer part in Z *)
Definition floor x := proj1_sig (floor_ex x).
Definition floor1 x := proj1_sig (floor1_ex x).
(** Interger part in nat *)
Definition nfloor x pr := proj1_sig (nfloor_ex x pr).
Definition nfloor1 x pr := proj1_sig (nfloor1_ex x pr).
(** More theorems about INR *)
Fixpoint pow2 (n : nat) : nat :=
match n with
| O => 1%nat
| S n => (2 * pow2 n)%nat
end.

Lemma pow2_INR (n : nat) : INR (pow2 n) = 2^n.