X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=helm%2Fsoftware%2Fmatita%2Fcontribs%2Fng_assembly%2Fnum%2Fquatern_lemmas.ma;h=d32aa0f3e83321a3f3ca587424a15c1782f1a51a;hb=5450fa91891df49587fedff6edd6179cf1bbc879;hp=49b70b81acfa3673c545d35db7202c8436e24882;hpb=b1c174cffd3c1d10383a52d63a6e662156fb0bb7;p=helm.git

diff --git a/helm/software/matita/contribs/ng_assembly/num/quatern_lemmas.ma b/helm/software/matita/contribs/ng_assembly/num/quatern_lemmas.ma
index 49b70b81a..d32aa0f3e 100755
--- a/helm/software/matita/contribs/ng_assembly/num/quatern_lemmas.ma
+++ b/helm/software/matita/contribs/ng_assembly/num/quatern_lemmas.ma
@@ -15,8 +15,8 @@
 (* ********************************************************************** *)
 (*                          Progetto FreeScale                            *)
 (*                                                                        *)
-(*   Sviluppato da: Cosimo Oliboni, oliboni@cs.unibo.it                   *)
-(*     Cosimo Oliboni, oliboni@cs.unibo.it                                *)
+(*   Sviluppato da: Ing. Cosimo Oliboni, oliboni@cs.unibo.it              *)
+(*   Ultima modifica: 05/08/2009                                          *)
 (*                                                                        *)
 (* ********************************************************************** *)
 
@@ -93,3 +93,33 @@ nlemma eq_to_eqqu : ∀n1,n2.n1 = n2 → eq_qu n1 n2 = true.
  ##| ##*: #H; napply (quatern_destruct … H)
  ##]
 nqed.
+
+nlemma decidable_qu : ∀x,y:quatern.decidable (x = y).
+ #x; #y;
+ nnormalize;
+ nelim x;
+ nelim y;
+ ##[ ##1,6,11,16: napply (or_introl (? = ?) (? ≠ ?) …); napply refl_eq
+ ##| ##*: napply (or_intror (? = ?) (? ≠ ?) …); nnormalize; #H; napply False_ind; napply (quatern_destruct … H)
+ ##]
+nqed.
+
+nlemma neqqu_to_neq : ∀n1,n2.eq_qu n1 n2 = false → n1 ≠ n2.
+ #n1; #n2;
+ ncases n1;
+ ncases n2;
+ nnormalize;
+ ##[ ##1,6,11,16: #H; napply (bool_destruct … H)
+ ##| ##*: #H; #H1; napply (quatern_destruct … H1)
+ ##]
+nqed.
+
+nlemma neq_to_neqqu : ∀n1,n2.n1 ≠ n2 → eq_qu n1 n2 = false.
+ #n1; #n2;
+ ncases n1;
+ ncases n2;
+ nnormalize;
+ ##[ ##1,6,11,16: #H; nelim (H (refl_eq …))
+ ##| ##*: #H; napply refl_eq
+ ##]
+nqed.