X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=matita%2Fmatita%2Flib%2Flambda-delta%2Fsubstitution%2Fthin.ma;h=00e52947de0b7fef67eaddd4e8d7b6772fd3fbe5;hb=1abd18f614b6691547662cc8608f259233b246c7;hp=03cc81b06bbb60eff18965fdaa8958b658713988;hpb=7b976a01aa6cedbfbef57ace183ce3fc0e2f22a9;p=helm.git

diff --git a/matita/matita/lib/lambda-delta/substitution/thin.ma b/matita/matita/lib/lambda-delta/substitution/thin.ma
index 03cc81b06..00e52947d 100644
--- a/matita/matita/lib/lambda-delta/substitution/thin.ma
+++ b/matita/matita/lib/lambda-delta/substitution/thin.ma
@@ -18,8 +18,18 @@ inductive thin: lenv → nat → nat → lenv → Prop ≝
    | thin_thin: ∀L1,L2,I,V,e.
                 thin L1 0 e L2 → thin (L1. ♭I V) 0 (e + 1) L2
    | thin_skip: ∀L1,L2,I,V1,V2,d,e.
-                thin L1 d e L2 → [d,e]← L1 / V1 ≡ V2 → 
+                thin L1 d e L2 → L1 ⊢ ↓[d,e] V1 ≡ V2 →
                 thin (L1. ♭I V1) (d + 1) e (L2. ♭I V2)
 .
 
-interpretation "thinning" 'RThin L1 d e L2 = (thin L1 d e L2).
+interpretation "thinning" 'RSubst L1 d e L2 = (thin L1 d e L2).
+
+(* the main properties ******************************************************)
+
+axiom thin_conf_ge: ∀d1,e1,L,L1. ↓[d1,e1] L ≡ L1 →
+                    ∀e2,L2. ↓[0,e2] L ≡ L2 → d1 + e1 ≤ e2 → ↓[0,e2-e1] L1 ≡ L2.
+
+axiom thin_conf_lt: ∀d1,e1,L,L1. ↓[d1,e1] L ≡ L1 →
+                    ∀e2,K2,I,V2. ↓[0,e2] L ≡ K2. ♭I V2 →
+                    e2 < d1 → let d ≝ d1 - e2 - 1 in
+                    ∃K1,V1. ↓[0,e2] L1 ≡ K1. ♭I V1 ∧ ↓[d,e1] K2 ≡ K1 ∧ ↑[d,e1] V1 ≡ V2.