--- a/src/HOL/Wellfounded.thy Fri Jun 11 17:14:01 2010 +0200
+++ b/src/HOL/Wellfounded.thy Fri Jun 11 17:14:02 2010 +0200
@@ -683,10 +683,8 @@
text{* Lexicographic combinations *}
definition
- lex_prod :: "[('a*'a)set, ('b*'b)set] => (('a*'b)*('a*'b))set"
- (infixr "<*lex*>" 80)
-where
- "ra <*lex*> rb == {((a,b),(a',b')). (a,a') : ra | a=a' & (b,b') : rb}"
+ lex_prod :: "('a \<times>'a) set \<Rightarrow> ('b \<times> 'b) set \<Rightarrow> (('a \<times> 'b) \<times> ('a \<times> 'b)) set" (infixr "<*lex*>" 80) where
+ [code del]: "ra <*lex*> rb = {((a, b), (a', b')). (a, a') \<in> ra \<or> a = a' \<and> (b, b') \<in> rb}"
lemma wf_lex_prod [intro!]: "[| wf(ra); wf(rb) |] ==> wf(ra <*lex*> rb)"
apply (unfold wf_def lex_prod_def)