- some additions and corrections

[helm.git] / matita / matita / contribs / lambda_delta / basic_2 / computation / xprs.ma

diff --git a/matita/matita/contribs/lambda_delta/basic_2/computation/xprs.ma b/matita/matita/contribs/lambda_delta/basic_2/computation/xprs.ma
index 775e136cbb884e29d1ec6940b3d24fe43f0be03a..c07de4dfd5e85a22da8169908e62de15834b7e60 100644 (file)
--- a/matita/matita/contribs/lambda_delta/basic_2/computation/xprs.ma
+++ b/matita/matita/contribs/lambda_delta/basic_2/computation/xprs.ma
@@ -47,18 +47,17 @@ lemma xprs_refl: ∀h,g,L,T. ⦃h, L⦄ ⊢ T ➸*[g] T.
 
 lemma xprs_strap1: ∀h,g,L,T1,T,T2.
                    ⦃h, L⦄ ⊢ T1 ➸*[g] T → ⦃h, L⦄ ⊢ T ➸[g] T2 → ⦃h, L⦄ ⊢ T1 ➸*[g] T2.
-/2 width=3/ qed.
+/2 width=3 by step/ qed. (**) (* NTypeChecker failure without trace *)
 
 lemma xprs_strap2: ∀h,g,L,T1,T,T2.
                    ⦃h, L⦄ ⊢ T1 ➸[g] T → ⦃h, L⦄ ⊢ T ➸*[g] T2 → ⦃h, L⦄ ⊢ T1 ➸*[g] T2.
-/2 width=3/ qed.
+/2 width=3 by TC_strap/ qed. (**) (* NTypeChecker failure without trace *)
 
 (* Basic inversion lemmas ***************************************************)
 (*
 axiom xprs_inv_cnf1: ∀L,T,U. L ⊢ T ➡* U → L ⊢ 𝐍⦃T⦄ → T = U.
-(*
 #L #T #U #H @(xprs_ind_dx … H) -T //
 #T0 #T #H1T0 #_ #IHT #H2T0
 lapply (H2T0 … H1T0) -H1T0 #H destruct /2 width=1/
 qed-.
-*)*)
+*)