diff -r 20b708827030 -r 5dfdc1464966 src/ZF/AC/WO1_WO8.ML
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/ZF/AC/WO1_WO8.ML	Thu May 18 11:51:23 1995 +0200
@@ -0,0 +1,30 @@
+(*  Title: 	ZF/AC/WO1_WO8.ML
+    ID:         $Id$
+    Author: 	Krzysztof Gr`abczewski
+
+The proof of WO8 <-> WO1 (Rubin & Rubin p. 6)
+*)
+
+(* ********************************************************************** *)
+(* Trivial implication "WO1 ==> WO8"					  *)
+(* ********************************************************************** *)
+
+goalw thy WO_defs "!!Z. WO1 ==> WO8";
+by (fast_tac ZF_cs 1);
+result();
+
+(* ********************************************************************** *)
+(* The proof of "WO8 ==> WO1" - faithful image of Rubin & Rubin's proof	  *)
+(* ********************************************************************** *)
+
+goalw thy WO_defs "!!Z. WO8 ==> WO1";
+by (resolve_tac [allI] 1);
+by (eres_inst_tac [("x","{{x}. x:A}")] allE 1);
+by (eresolve_tac [impE] 1);
+by (fast_tac (AC_cs addSEs [lam_sing_bij RS bij_is_inj RS
+			well_ord_rvimage]) 2);
+by (res_inst_tac [("x","lam a:{{x}. x:A}. THE x. a={x}")] exI 1);
+by (fast_tac (ZF_cs addSEs [RepFunE, singleton_eq_iff RS iffD1 RS sym]
+		addSIs [lam_type, singletonI]
+		addIs [the_equality RS ssubst]) 1);
+result();
\ No newline at end of file