src/HOL/UNITY/Simple/Channel.thy

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/HOL/UNITY/Simple/Channel.thy	Mon Mar 05 15:47:11 2001 +0100
@@ -0,0 +1,30 @@
+(*  Title:      HOL/UNITY/Channel
+    ID:         $Id$
+    Author:     Lawrence C Paulson, Cambridge University Computer Laboratory
+    Copyright   1998  University of Cambridge
+
+Unordered Channel
+
+From Misra, "A Logic for Concurrent Programming" (1994), section 13.3
+*)
+
+Channel = WFair + Option + 
+
+types state = nat set
+
+consts
+  F :: state program
+
+constdefs
+  minSet :: nat set => nat option
+    "minSet A == if A={} then None else Some (LEAST x. x:A)"
+
+rules
+
+  UC1  "F : (minSet -` {Some x}) co (minSet -` (Some`atLeast x))"
+
+  (*  UC1  "F : {s. minSet s = x} co {s. x <= minSet s}"  *)
+
+  UC2  "F : (minSet -` {Some x}) leadsTo {s. x ~: s}"
+
+end