X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=matita%2Fmatita%2Flib%2Flambda-delta%2Fsubstitution%2Fleq.ma;h=b0e28d48e42701b41f2f1c46899ae5ab6949868f;hb=14fef03bcc79583593a129bf9c68bdf690a10eb7;hp=3c7981566eda07fa25cedbbb9d429d9c34f9540f;hpb=baccd5a2f3b79c295b1f9444575bfb351577634e;p=helm.git

diff --git a/matita/matita/lib/lambda-delta/substitution/leq.ma b/matita/matita/lib/lambda-delta/substitution/leq.ma
index 3c7981566..b0e28d48e 100644
--- a/matita/matita/lib/lambda-delta/substitution/leq.ma
+++ b/matita/matita/lib/lambda-delta/substitution/leq.ma
@@ -9,7 +9,7 @@
      \ /
       V_______________________________________________________________ *)
 
-include "lambda-delta/syntax/lenv.ma".
+include "lambda-delta/syntax/length.ma".
 
 (* LOCAL ENVIRONMENT EQUALITY ***********************************************)
 
@@ -37,12 +37,16 @@ lemma leq_sym: ∀L1,L2,d,e. L1 [d, e] ≈ L2 → L2 [d, e] ≈ L1.
 #L1 #L2 #d #e #H elim H -H L1 L2 d e /2/
 qed.
 
-lemma leq_skip_lt: ∀L1,L2,d,e. leq L1 (d - 1) e L2 → 0 < d →
+lemma leq_skip_lt: ∀L1,L2,d,e. L1 [d - 1, e] ≈ L2 → 0 < d →
                    ∀I1,I2,V1,V2. L1. 𝕓{I1} V1 [d, e] ≈ L2. 𝕓{I2} V2.
 
 #L1 #L2 #d #e #HL12 #Hd >(plus_minus_m_m d 1) /2/ 
 qed.
 
+lemma leq_fwd_length: ∀L1,L2,d,e. L1 [d, e] ≈ L2 → |L1| = |L2|.
+#L1 #L2 #d #e #H elim H -H L1 L2 d e; normalize //
+qed.  
+
 (* Basic inversion lemmas ***************************************************)
 
 lemma leq_inv_sort1_aux: ∀L1,L2,d,e. L1 [d, e] ≈ L2 → L1 = ⋆ → L2 = ⋆.