doc-src/TutorialI/Recdef/termination.thy
changeset 10186 499637e8f2c6
parent 10171 59d6633835fa
child 10522 ed3964d1f1a4
--- a/doc-src/TutorialI/Recdef/termination.thy	Wed Oct 11 00:03:22 2000 +0200
+++ b/doc-src/TutorialI/Recdef/termination.thy	Wed Oct 11 09:09:06 2000 +0200
@@ -81,21 +81,6 @@
 about @{term f}. In most cases this is more cumbersome than proving things
 up front.
 %FIXME, with one exception: nested recursion.
-
-Although all the above examples employ measure functions, \isacommand{recdef}
-allows arbitrary wellfounded relations. For example, termination of
-Ackermann's function requires the lexicographic product @{text"<*lex*>"}:
-*}
-
-consts ack :: "nat\<times>nat \<Rightarrow> nat";
-recdef ack "measure(\<lambda>m. m) <*lex*> measure(\<lambda>n. n)"
-  "ack(0,n)         = Suc n"
-  "ack(Suc m,0)     = ack(m, 1)"
-  "ack(Suc m,Suc n) = ack(m,ack(Suc m,n))";
-
-text{*\noindent
-For details see the manual~\cite{isabelle-HOL} and the examples in the
-library.
 *}
 
 (*<*)