From: Stefano Zacchiroli <zack@upsilon.cc>
Date: Mon, 26 Sep 2005 16:27:18 +0000 (+0000)
Subject: function composition notation
X-Git-Tag: V_0_7_2_3~310
X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=commitdiff_plain;h=4c002f24d149e7db6525a463268feab09ec8a938;p=helm.git

function composition notation
---

diff --git a/helm/matita/library/higher_order_defs/functions.ma b/helm/matita/library/higher_order_defs/functions.ma
index 321ae46b7..78c2e2f89 100644
--- a/helm/matita/library/higher_order_defs/functions.ma
+++ b/helm/matita/library/higher_order_defs/functions.ma
@@ -16,6 +16,17 @@ set "baseuri" "cic:/matita/higher_order_defs/functions/".
 
 include "logic/equality.ma".
 
+definition compose \def
+  \lambda A,B,C:Type.\lambda f:(B\to C).\lambda g:(A\to B).\lambda x:A.
+  f (g x).
+
+notation "hvbox(a break \circ b)" 
+  left associative with precedence 70
+for @{ 'compose $a $b }.
+
+interpretation "function composition" 'compose f g =
+  (cic:/matita/higher_order_defs/functions/compose.con _ _ _ f g).
+
 definition injective: \forall A,B:Type.\forall f:A \to B.Prop
 \def \lambda A,B.\lambda f.
   \forall x,y:A.f x = f y \to x=y.
@@ -33,6 +44,14 @@ definition symmetric2: \forall A,B:Type.\forall f:A \to A\to B.Prop
 definition associative: \forall A:Type.\forall f:A \to A\to A.Prop
 \def \lambda A.\lambda f.\forall x,y,z.f (f x y) z = f x (f y z).
 
+theorem eq_f_g_h:
+  \forall A,B,C,D:Type.
+  \forall f:C \to D.\forall g:B \to C.\forall h:A \to B.
+  f \circ (g \circ h) = (f \circ g) \circ h.
+  intros.
+  reflexivity.
+qed.
+
 (* functions and relations *)
 definition monotonic : \forall A:Type.\forall R:A \to A \to Prop.
 \forall f:A \to A.Prop \def