src/ZF/AC/AC1_WO2.ML
changeset 1123 5dfdc1464966
child 1196 d43c1f7a53fe
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/ZF/AC/AC1_WO2.ML	Thu May 18 11:51:23 1995 +0200
@@ -0,0 +1,23 @@
+(*  Title: 	ZF/AC/AC1_WO2.ML
+    ID:         $Id$
+    Author: 	Krzysztof Gr`abczewski
+
+The proof of AC1 ==> WO2
+*)
+
+open AC1_WO2;
+
+val [prem] = goal thy "f : (PROD X:Pow(x) - {0}. X) ==>  \
+\	?g(f) : bij(x, LEAST i. HH(lam X:Pow(x)-{0}. {f`X}, x, i) = {x})";
+by (resolve_tac [bij_Least_HH_x RS bij_converse_bij] 1);
+by (resolve_tac [f_subsets_imp_UN_HH_eq_x] 1);
+by (resolve_tac [lam_type RS apply_type] 1 THEN (assume_tac 2));
+by (fast_tac (AC_cs addSDs [equals0D, prem RS apply_type]) 1);
+by (fast_tac (AC_cs addSIs [prem RS Pi_weaken_type]) 1);
+val lemma1 = uresult();
+
+goalw thy [AC1_def, WO2_def, eqpoll_def] "!!Z. AC1 ==> WO2";
+by (resolve_tac [allI] 1);
+by (eres_inst_tac [("x","Pow(A)-{0}")] allE 1);
+by (fast_tac (AC_cs addSDs [lemma1] addSIs [Ord_Least]) 1);
+result();