update in ground_2

[helm.git] / matita / matita / contribs / lambdadelta / ground_2 / relocation / nstream_after.ma

diff --git a/matita/matita/contribs/lambdadelta/ground_2/relocation/nstream_after.ma b/matita/matita/contribs/lambdadelta/ground_2/relocation/nstream_after.ma
index 0f21ba6c3774da6595e4df07715653c882f7f8d9..6ce6fa476a68bc4e2ed4587653a9f4e0d25b2677 100644 (file)
--- a/matita/matita/contribs/lambdadelta/ground_2/relocation/nstream_after.ma
+++ b/matita/matita/contribs/lambdadelta/ground_2/relocation/nstream_after.ma
@@ -151,3 +151,8 @@ qed-.
 lemma after_inv_apply: ∀f2,f1,f,n2,n1,n. n2⨮f2 ⊚ n1⨮f1 ≘ n⨮f →
                        (n2⨮f2)@❴n1❵ = n ∧ (⫰*[n1]f2) ⊚ f1 ≘ f.
 /3 width=3 by after_fwd_tls, after_fwd_hd, conj/ qed-.
+
+(* Properties on apply ******************************************************)
+
+lemma compose_apply (f2) (f1) (i): f2@❴f1@❴i❵❵ = (f2∘f1)@❴i❵.
+/4 width=6 by after_fwd_at, at_inv_total, sym_eq/ qed.