
diff -r 000000000000 -r a5a9c433f639 src/ZF/ex/ramsey.thy
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/ZF/ex/ramsey.thy	Thu Sep 16 12:20:38 1993 +0200
@@ -0,0 +1,46 @@
+(*  Title: 	ZF/ex/ramsey.thy
+    ID:         $Id$
+    Author: 	Lawrence C Paulson, Cambridge University Computer Laboratory
+    Copyright   1992  University of Cambridge
+
+Ramsey's Theorem (finite exponent 2 version)
+
+Based upon the article
+    D Basin and M Kaufmann,
+    The Boyer-Moore Prover and Nuprl: An Experimental Comparison.
+    In G Huet and G Plotkin, editors, Logical Frameworks.
+    (CUP, 1991), pages 89--119
+
+See also
+    M Kaufmann,
+    An example in NQTHM: Ramsey's Theorem
+    Internal Note, Computational Logic, Inc., Austin, Texas 78703
+    Available from the author: kaufmann@cli.com
+*)
+
+Ramsey = Arith +
+consts
+  Symmetric   		:: "i=>o"
+  Atleast     		:: "[i,i]=>o"
+  Clique,Indept,Ramsey	:: "[i,i,i]=>o"
+
+rules
+
+  Symmetric_def
+    "Symmetric(E) == (ALL x y. <x,y>:E --> <y,x>:E)"
+
+  Clique_def
+    "Clique(C,V,E) == (C<=V) & (ALL x:C. ALL y:C. ~ x=y --> <x,y>:E)"
+
+  Indept_def
+    "Indept(I,V,E) == (I<=V) & (ALL x:I. ALL y:I. ~ x=y --> ~ <x,y>:E)"
+
+  Atleast_def
+    "Atleast(n,S) == (EX f. f: inj(n,S))"
+
+  Ramsey_def
+    "Ramsey(n,i,j) == ALL V E. Symmetric(E) & Atleast(n,V) -->  \
+\         (EX C. Clique(C,V,E) & Atleast(i,C)) |       \
+\         (EX I. Indept(I,V,E) & Atleast(j,I))"
+
+end




