X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=matita%2Fmatita%2Fcontribs%2Flambdadelta%2Fground_2%2Flib%2Flist.ma;h=3ec2d22c7dafab3ca4dd377c85bd0d55718cd9c9;hb=397413c4196f84c81d61ba7dd79b54ab1c428ebb;hp=baa9179e911dfd49ebd32ec57c2a638068c23369;hpb=24ba1bb3f67505d3e384747ff90d26d3996bd3f5;p=helm.git

diff --git a/matita/matita/contribs/lambdadelta/ground_2/lib/list.ma b/matita/matita/contribs/lambdadelta/ground_2/lib/list.ma
index baa9179e9..3ec2d22c7 100644
--- a/matita/matita/contribs/lambdadelta/ground_2/lib/list.ma
+++ b/matita/matita/contribs/lambdadelta/ground_2/lib/list.ma
@@ -28,7 +28,7 @@ interpretation "cons (list)" 'Cons hd tl = (cons ? hd tl).
 
 rec definition length (A:Type[0]) (l:list A) on l ≝ match l with
 [ nil      ⇒ 0
-| cons _ l ⇒ ⫯(length A l)
+| cons _ l ⇒ ↑(length A l)
 ].
 
 interpretation "length (list)"
@@ -45,7 +45,7 @@ rec definition all A (R:predicate A) (l:list A) on l ≝
 lemma length_nil (A:Type[0]): |nil A| = 0.
 // qed.
 
-lemma length_cons (A:Type[0]) (l:list A) (a:A): |a@l| = ⫯|l|.
+lemma length_cons (A:Type[0]) (l:list A) (a:A): |a@l| = ↑|l|.
 // qed.
 
 (* Basic inversion lemmas on length *****************************************)
@@ -57,12 +57,12 @@ qed-.
 lemma length_inv_zero_sn (A:Type[0]) (l:list A): 0 = |l| → l = ◊.
 /2 width=1 by length_inv_zero_dx/ qed-.
 
-lemma length_inv_succ_dx (A:Type[0]) (l:list A) (x): |l| = ⫯x →
+lemma length_inv_succ_dx (A:Type[0]) (l:list A) (x): |l| = ↑x →
                          ∃∃tl,a. x = |tl| & l = a @ tl.
 #A * /2 width=4 by ex2_2_intro/
 >length_nil #x #H destruct
 qed-.
 
-lemma length_inv_succ_sn (A:Type[0]) (l:list A) (x): ⫯x = |l| →
+lemma length_inv_succ_sn (A:Type[0]) (l:list A) (x): ↑x = |l| →
                          ∃∃tl,a. x = |tl| & l = a @ tl.
 /2 width=1 by length_inv_succ_dx/ qed.