src/Pure/thm.ML

--- a/src/Pure/thm.ML	Wed Apr 20 13:17:25 2011 +0200
+++ b/src/Pure/thm.ML	Wed Apr 20 13:54:07 2011 +0200
@@ -611,7 +611,7 @@
                maxidx = maxidx, shyps = shyps, hyps = [], tpairs = [], prop = prop})
            end);
   in
-    (case get_first get_ax (theory :: Theory.ancestors_of theory) of
+    (case get_first get_ax (Theory.nodes_of theory) of
       SOME thm => thm
     | NONE => raise THEORY ("No axiom " ^ quote name, [theory]))
   end;