X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=matita%2Fmatita%2Fcontribs%2Flambdadelta%2Fbasic_2%2Freduction%2Flpr.ma;h=04d5d1a294f09cd6c0f75334945950372e0d6abe;hb=0679e5d5a305a43a8b4b01a5ac4c7caffacc73b9;hp=1b3100ffbc9effd3404d6c118bd6f8970a8270b6;hpb=09af7a9751464291ec3f32fb80c92fe1accdbf88;p=helm.git

diff --git a/matita/matita/contribs/lambdadelta/basic_2/reduction/lpr.ma b/matita/matita/contribs/lambdadelta/basic_2/reduction/lpr.ma
index 1b3100ffb..04d5d1a29 100644
--- a/matita/matita/contribs/lambdadelta/basic_2/reduction/lpr.ma
+++ b/matita/matita/contribs/lambdadelta/basic_2/reduction/lpr.ma
@@ -46,6 +46,10 @@ lemma lpr_inv_pair2: ∀I,L1,K2,V2. L1 ⊢ ➡ K2. ⓑ{I} V2 →
 lemma lpr_refl: ∀L. L ⊢ ➡ L.
 /2 width=1 by lpx_sn_refl/ qed.
 
+lemma lpr_pair: ∀I,K1,K2,V1,V2. K1 ⊢ ➡ K2 → K1 ⊢ V1 ➡ V2 →
+                K1.ⓑ{I}V1 ⊢ ➡ K2.ⓑ{I}V2.
+/2 width=1/ qed.
+
 lemma lpr_append: ∀K1,K2. K1 ⊢ ➡ K2 → ∀L1,L2. L1 ⊢ ➡ L2 →
                   L1 @@ K1 ⊢ ➡ L2 @@ K2.
 /3 width=1 by lpx_sn_append, cpr_append/ qed.