X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=matita%2Flibrary%2Fassembly%2Fexadecimal.ma;h=fb1a14ede914299c6b2e9342296e846c39dc54b0;hb=dfbd010fe5a46d049849913bc23000289893ea4f;hp=3a4e35da40384455eefebbd252648dbcfc9ea984;hpb=9655a931c73be820d876da7b23fe54b55fd60c14;p=helm.git

diff --git a/matita/library/assembly/exadecimal.ma b/matita/library/assembly/exadecimal.ma
index 3a4e35da4..fb1a14ede 100644
--- a/matita/library/assembly/exadecimal.ma
+++ b/matita/library/assembly/exadecimal.ma
@@ -14,7 +14,7 @@
 
 set "baseuri" "cic:/matita/assembly/exadecimal/".
 
-include "extra.ma".
+include "assembly/extra.ma".
 
 inductive exadecimal : Type ≝
    x0: exadecimal
@@ -836,6 +836,13 @@ lemma nat_of_exadecimal_exadecimal_of_nat:
   ]
 qed.
 
+lemma exadecimal_of_nat_nat_of_exadecimal:
+ ∀b.exadecimal_of_nat (nat_of_exadecimal b) = b.
+ intro;
+ elim b;
+ reflexivity.
+qed.
+
 lemma plusex_ok:
  ∀b1,b2,c.
   match plusex b1 b2 c with
@@ -904,9 +911,20 @@ lemma eqex_true_to_eq: ∀b,b'. eqex b b' = true → b=b'.
  first [ reflexivity | destruct H ].
 qed.
  
+lemma eqex_false_to_not_eq: ∀b,b'. eqex b b' = false → b ≠ b'.
+ intros 2;
+ elim b 0;
+ elim b' 0;
+ simplify;
+ intro;
+ try (destruct H);
+ intro K;
+ destruct K.
+qed.
+ 
 (*
 lemma xpred_S: ∀b. xpred (exadecimal_of_nat (S b)) = exadecimal_of_nat b.
  intros;
  rewrite > exadecimal_of_nat_mod;
  rewrite > exadecimal_of_nat_mod in ⊢ (? ? ? %);
-*)
\ No newline at end of file
+*)