X-Git-Url: http://matita.cs.unibo.it/gitweb/?p=helm.git;a=blobdiff_plain;f=matita%2Fmatita%2Fcontribs%2Flambdadelta%2Fground%2Flib%2Fstream.ma;h=ff7a6c3493dfb2bef0c2792c5836e36cd1e8674d;hp=d0e05e17e067632d71937926eba6a6494969265c;hb=ae626612bff9c3746dd7647bbada791c737e348c;hpb=4d232392091ee233afc26ecf3120dd5f5c6a33c8

diff --git a/matita/matita/contribs/lambdadelta/ground/lib/stream.ma b/matita/matita/contribs/lambdadelta/ground/lib/stream.ma
index d0e05e17e..ff7a6c349 100644
--- a/matita/matita/contribs/lambdadelta/ground/lib/stream.ma
+++ b/matita/matita/contribs/lambdadelta/ground/lib/stream.ma
@@ -30,3 +30,11 @@ interpretation
 lemma stream_rew (A) (t:stream A): match t with [ stream_cons a u ⇒ a ⨮ u ] = t.
 #A * //
 qed.
+
+(* Basic inversions *********************************************************)
+
+lemma eq_inv_stream_cons_bi (A) (a1,a2:A) (u1) (u2):
+      a1 ⨮ u1 = a2 ⨮ u2 → ∧∧ a1 = a2 & u1 = u2.
+#A #a1 #a2 #u1 #u2 #H destruct
+/2 width=1 by conj/
+qed-.