set "baseuri" "cic:/matita/nat/compare".
-include "nat/orders.ma".
include "datatypes/bool.ma".
include "datatypes/compare.ma".
+include "nat/orders.ma".
let rec eqb n m \def
match n with
simplify.apply not_eq_O_S.
intro.
simplify.
-intro. apply not_eq_O_S n1 ?.apply sym_eq.assumption.
+intro. apply not_eq_O_S n1.apply sym_eq.assumption.
intros.simplify.
generalize in match H.
elim (eqb n1 m1).
qed.
theorem leb_elim: \forall n,m:nat. \forall P:bool \to Prop.
-(n \leq m \to (P true)) \to (\not (n \leq m) \to (P false)) \to
+(n \leq m \to (P true)) \to (\lnot (n \leq m) \to (P false)) \to
P (leb n m).
intros.
cut
intro.simplify.apply le_S_S. apply le_O_n.
intros 2.simplify.elim (nat_compare n1 m1).
simplify. apply le_S_S.apply H.
-simplify. apply le_S_S.apply H.
simplify. apply eq_f. apply H.
+simplify. apply le_S_S.apply H.
qed.
theorem nat_compare_n_m_m_n: \forall n,m:nat.
apply Hcut.apply nat_compare_to_Prop.
elim (nat_compare n m).
apply (H H3).
-apply (H2 H3).
apply (H1 H3).
+apply (H2 H3).
qed.