X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=matita%2Fmatita%2Fcontribs%2Flambdadelta%2Fground%2Flib%2Fstream_hdtl.ma;h=468f306de0bbcbd4429b6a4607b69779e0a31e8e;hb=8bbe582d87984526f40182c4409cbfd43108cb79;hp=4a3640baed498488974f0c6e34ec370343c8d807;hpb=6604a232815858a6c75dd25ac45abd68438077ff;p=helm.git

diff --git a/matita/matita/contribs/lambdadelta/ground/lib/stream_hdtl.ma b/matita/matita/contribs/lambdadelta/ground/lib/stream_hdtl.ma
index 4a3640bae..468f306de 100644
--- a/matita/matita/contribs/lambdadelta/ground/lib/stream_hdtl.ma
+++ b/matita/matita/contribs/lambdadelta/ground/lib/stream_hdtl.ma
@@ -12,32 +12,39 @@
 (*                                                                        *)
 (**************************************************************************)
 
-include "ground/notation/functions/downspoon_2.ma".
-include "ground/lib/stream_eq.ma".
+include "ground/notation/functions/downharpoonleft_2.ma".
+include "ground/notation/functions/downharpoonright_2.ma".
+include "ground/lib/stream.ma".
 
 (* HEAD AND TAIL FOR STREAMS ************************************************)
 
-definition stream_hd (A:Type[0]): stream A → A ≝
-           λt. match t with [ stream_cons a _ ⇒ a ].
+definition stream_hd (A:Type[0]): stream A → A.
+#A * #a #_ @a
+defined.
 
-definition stream_tl (A:Type[0]): stream A → stream A ≝
-           λt. match t with [ stream_cons _ t ⇒ t ].
+interpretation
+  "head (streams)"
+  'DownHarpoonLeft A t = (stream_hd A t).
+
+definition stream_tl (A:Type[0]): stream A → stream A.
+#A * #_ #t @t
+defined.
 
 interpretation
   "tail (streams)"
-  'DownSpoon A t = (stream_tl A t).
+  'DownHarpoonRight A t = (stream_tl A t).
 
 (* Basic constructions ******************************************************)
 
 lemma stream_hd_cons (A) (a) (t):
-      a = stream_hd A (a⨮t).
+      a = ⇃{A}(a⨮t).
 // qed.
 
 lemma stream_tl_cons (A) (a) (t):
-      t = ⫰{A}(a⨮t).
+      t = ⇂{A}(a⨮t).
 // qed.
 
-lemma eq_stream_split_hd_tl (A) (t):
-      stream_hd … t ⨮ ⫰t ≗{A} t.
+lemma stream_split_tl (A) (t):
+      ⇃{A}t ⨮ ⇂t = t.
 #A * //
 qed.