X-Git-Url: http://matita.cs.unibo.it/gitweb/?p=helm.git;a=blobdiff_plain;f=matita%2Fmatita%2Fcontribs%2Flambdadelta%2Fbasic_2%2Fsyntax%2Flenv_length.ma;h=440c5497a296d5840d954a31b72fed0e89074836;hp=8b7ccd58207a7b1fc92fc4203da6f70612a7982c;hb=222044da28742b24584549ba86b1805a87def070;hpb=1c8e230b1d81491b38126900d76201fb84303ced

diff --git a/matita/matita/contribs/lambdadelta/basic_2/syntax/lenv_length.ma b/matita/matita/contribs/lambdadelta/basic_2/syntax/lenv_length.ma
index 8b7ccd582..440c5497a 100644
--- a/matita/matita/contribs/lambdadelta/basic_2/syntax/lenv_length.ma
+++ b/matita/matita/contribs/lambdadelta/basic_2/syntax/lenv_length.ma
@@ -18,20 +18,18 @@ include "basic_2/syntax/lenv.ma".
 
 rec definition length L ≝ match L with
 [ LAtom     ⇒ 0
-| LBind L _ ⇒ ⫯(length L)
+| LBind L _ ⇒ ↑(length L)
 ].
 
 interpretation "length (local environment)" 'card L = (length L).
 
-definition length2 (L1) (L2): nat ≝ |L1| + |L2|. 
-
 (* Basic properties *********************************************************)
 
 lemma length_atom: |⋆| = 0.
 // qed.
 
 (* Basic_2A1: uses: length_pair *)
-lemma length_bind: ∀I,L. |L.ⓘ{I}| = ⫯|L|.
+lemma length_bind: ∀I,L. |L.ⓘ{I}| = ↑|L|.
 // qed.
 
 (* Basic inversion lemmas ***************************************************)
@@ -45,7 +43,7 @@ lemma length_inv_zero_sn: ∀L. 0 = |L| → L = ⋆.
 /2 width=1 by length_inv_zero_dx/ qed-.
 
 (* Basic_2A1: was: length_inv_pos_dx *)
-lemma length_inv_succ_dx: ∀n,L. |L| = ⫯n →
+lemma length_inv_succ_dx: ∀n,L. |L| = ↑n →
                           ∃∃I,K. |K| = n & L = K. ⓘ{I}.
 #n *
 [ >length_atom #H destruct
@@ -54,7 +52,7 @@ lemma length_inv_succ_dx: ∀n,L. |L| = ⫯n →
 qed-.
 
 (* Basic_2A1: was: length_inv_pos_sn *)
-lemma length_inv_succ_sn: ∀n,L. ⫯n = |L| →
+lemma length_inv_succ_sn: ∀n,L. ↑n = |L| →
                           ∃∃I,K. n = |K| & L = K. ⓘ{I}.
 #n #L #H lapply (sym_eq ??? H) -H 
 #H elim (length_inv_succ_dx … H) -H /2 width=4 by ex2_2_intro/