X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=matita%2Fmatita%2Fcontribs%2Flambda_delta%2Fbasic_2%2Fcomputation%2Fcprs_tstc.ma;h=35917450311b382e12b463868adda731a926d522;hb=a386e0eb6b20909ae78c825203d77647b8fde30c;hp=c7f49d1cf1f4fb6a9fc25235eadd6a4b08e500ed;hpb=bbac36729dab046d61019081c1523af06d876103;p=helm.git

diff --git a/matita/matita/contribs/lambda_delta/basic_2/computation/cprs_tstc.ma b/matita/matita/contribs/lambda_delta/basic_2/computation/cprs_tstc.ma
index c7f49d1cf..359174503 100644
--- a/matita/matita/contribs/lambda_delta/basic_2/computation/cprs_tstc.ma
+++ b/matita/matita/contribs/lambda_delta/basic_2/computation/cprs_tstc.ma
@@ -20,6 +20,11 @@ include "basic_2/computation/cprs_lcprs.ma".
 
 (* Forward lemmas involving same top term constructor ***********************)
 
+lemma cprs_fwd_cnf: ∀L,T. L ⊢ 𝐍[T] → ∀U. L ⊢ T ➡* U → T ≃ U.
+#L #T #HT #U #H
+>(cprs_inv_cnf1 … H HT) -L -T //
+qed-.
+
 (* Basic_1: was: pr3_iso_beta *)
 lemma cprs_fwd_beta: ∀L,V,W,T,U. L ⊢ ⓐV. ⓛW. T ➡* U →
                      ⓐV. ⓛW. T ≃ U ∨ L ⊢ ⓓV. T ➡* U.