diff -r a6205c6203ea -r 9f11af8f7ef9 src/Pure/theory.ML
--- a/src/Pure/theory.ML	Thu Apr 27 12:11:56 2006 +0200
+++ b/src/Pure/theory.ML	Thu Apr 27 15:06:35 2006 +0200
@@ -144,7 +144,7 @@
 val oracle_space = #1 o #oracles o rep_theory;
 
 val axioms_of = Symtab.dest o #2 o #axioms o rep_theory;
-fun all_axioms_of thy = List.concat (map axioms_of (thy :: ancestors_of thy));
+fun all_axioms_of thy = maps axioms_of (thy :: ancestors_of thy);
 
 val defs_of = #defs o rep_theory;