--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/HOLCF/IOA/Modelcheck/Ring3.thy	Thu Apr 22 11:09:05 1999 +0200
@@ -0,0 +1,90 @@
+Ring3 = MuIOAOracle +
+
+datatype token = Leader | id0 | id1 | id2 | id3 | id4
+datatype Comm = Zero_One token | One_Two token | Two_Zero token |
+		Leader_Zero | Leader_One | Leader_Two
+
+consts
+Greater :: [token, token] => bool
+
+defs
+Greater_def
+"Greater x y == (x~=Leader & x~=id0 & y=id0) | (x=id4 & y~=id4 & y~=Leader) | (x=id2 & y=id1) | (x=id3 & y=id1) | (x=id3 & y=id2)"
+
+(* the ring is the composition of aut0, aut1 and aut2 *)
+automaton aut0 =
+signature
+actions Comm
+inputs "Two_Zero t"
+outputs "Zero_One t","Leader_Zero"
+states
+idf :: token
+initially "idf=id0 | idf = id3"
+transitions
+"Two_Zero t"
+transrel "if (t=id0 | t=id3) then (idf'=Leader) else (if (Greater t idf) then (idf'=t) else (idf'=idf))"
+"Zero_One t"
+pre "t=idf"
+"Leader_Zero"
+pre "idf=Leader"
+
+automaton aut1 =
+signature
+actions Comm
+inputs "Zero_One t"
+outputs "One_Two t","Leader_One"
+states
+idf :: token
+initially "idf=id1 | idf=id4"
+transitions
+"Zero_One t"
+transrel "if (t=id1 | t=id4) then (idf'=Leader) else (if (Greater t idf) then (idf'=t) else (idf'=idf))"
+"One_Two t"
+pre "t=idf"
+"Leader_One"
+pre "idf=Leader"
+
+automaton aut2 =
+signature
+actions Comm
+inputs "One_Two t"
+outputs "Two_Zero t","Leader_Two"
+states
+idf :: token
+initially "idf=id2"
+transitions
+"One_Two t"
+transrel "if (t=id2) then (idf'=Leader) else (if (Greater t idf) then (idf'=t) else (idf'=idf))"
+"Two_Zero t"
+pre "t=idf"
+"Leader_Two"
+pre "idf=Leader"
+
+automaton ring = compose aut0,aut1,aut2
+
+(* one_leader expresses property that at most one component declares itself to leader *)
+automaton one_leader =
+signature
+actions Comm
+outputs "Zero_One t","One_Two t","Two_Zero t","Leader_Zero","Leader_One","Leader_Two" 
+states
+leader :: token
+initially "leader=Leader"
+transitions
+"Zero_One t"
+pre "True"
+"One_Two t"
+pre "True"
+"Two_Zero t"
+pre "True" 
+"Leader_Zero"
+pre "leader=id0 | leader=Leader"
+post leader:="id0"
+"Leader_One"
+pre "leader=id1 | leader=Leader"
+post leader:="id1" 
+"Leader_Two"
+pre "leader=id2 | leader=Leader"
+post leader:="id2"
+
+end