X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;ds=sidebyside;f=helm%2Fsoftware%2Fmatita%2Fcontribs%2FLAMBDA-TYPES%2FBase-1%2Fext%2Farith.ma;h=e8a076513f82c7c32ee94ed0af4ed0543964f4e7;hb=fdda444a05fe4c68c925cd94e4e3a38c93d0c35f;hp=1ce93fd7f9333e9ee1507d48101ecab6fa0760ea;hpb=9376f52b7f5890d924ae7d93bcae2af9e516126d;p=helm.git

diff --git a/helm/software/matita/contribs/LAMBDA-TYPES/Base-1/ext/arith.ma b/helm/software/matita/contribs/LAMBDA-TYPES/Base-1/ext/arith.ma
index 1ce93fd7f..e8a076513 100644
--- a/helm/software/matita/contribs/LAMBDA-TYPES/Base-1/ext/arith.ma
+++ b/helm/software/matita/contribs/LAMBDA-TYPES/Base-1/ext/arith.ma
@@ -184,6 +184,14 @@ theorem le_Sx_x:
  \lambda (x: nat).(\lambda (H: (le (S x) x)).(\lambda (P: Prop).(let H0 \def 
 le_Sn_n in (False_ind P (H0 x H))))).
 
+theorem le_n_pred:
+ \forall (n: nat).(\forall (m: nat).((le n m) \to (le (pred n) (pred m))))
+\def
+ \lambda (n: nat).(\lambda (m: nat).(\lambda (H: (le n m)).(le_ind n (\lambda 
+(n0: nat).(le (pred n) (pred n0))) (le_n (pred n)) (\lambda (m0: 
+nat).(\lambda (_: (le n m0)).(\lambda (H1: (le (pred n) (pred m0))).(le_trans 
+(pred n) (pred m0) m0 H1 (le_pred_n m0))))) m H))).
+
 theorem minus_le:
  \forall (x: nat).(\forall (y: nat).(le (minus x y) x))
 \def
@@ -264,6 +272,14 @@ theorem le_trans_plus_r:
  \lambda (x: nat).(\lambda (y: nat).(\lambda (z: nat).(\lambda (H: (le (plus 
 x y) z)).(le_trans y (plus x y) z (le_plus_r x y) H)))).
 
+theorem lt_x_O:
+ \forall (x: nat).((lt x O) \to (\forall (P: Prop).P))
+\def
+ \lambda (x: nat).(\lambda (H: (le (S x) O)).(\lambda (P: Prop).(let H_y \def 
+(le_n_O_eq (S x) H) in (let H0 \def (eq_ind nat O (\lambda (ee: nat).(match 
+ee in nat return (\lambda (_: nat).Prop) with [O \Rightarrow True | (S _) 
+\Rightarrow False])) I (S x) H_y) in (False_ind P H0))))).
+
 theorem le_gen_S:
  \forall (m: nat).(\forall (x: nat).((le (S m) x) \to (ex2 nat (\lambda (n: 
 nat).(eq nat x (S n))) (\lambda (n: nat).(le m n)))))
@@ -586,3 +602,12 @@ d h) n)).(let H0 \def (le_trans d (plus d h) n (le_plus_l d h) H) in (let H1
 (le_plus_minus_sym h n (le_trans_plus_r d h n H))) in (le_S d (minus n h) 
 (le_minus d n h H))))))).
 
+theorem lt_x_pred_y:
+ \forall (x: nat).(\forall (y: nat).((lt x (pred y)) \to (lt (S x) y)))
+\def
+ \lambda (x: nat).(\lambda (y: nat).(nat_ind (\lambda (n: nat).((lt x (pred 
+n)) \to (lt (S x) n))) (\lambda (H: (lt x O)).(lt_x_O x H (lt (S x) O))) 
+(\lambda (n: nat).(\lambda (_: (((lt x (pred n)) \to (lt (S x) n)))).(\lambda 
+(H0: (lt x n)).(le_S_n (S (S x)) (S n) (le_n_S (S (S x)) (S n) (le_n_S (S x) 
+n H0)))))) y)).
+