diff -r f8a0e8b9bcd8 -r 2ceb11a2e190 doc-src/Tutorial/Recdef/ack
--- a/doc-src/Tutorial/Recdef/ack	Thu Jul 06 00:09:45 2000 +0200
+++ b/doc-src/Tutorial/Recdef/ack	Thu Jul 06 09:46:56 2000 +0200
@@ -1,5 +1,5 @@
 consts ack :: "nat*nat => nat"
-recdef ack "measure(%m. m) ** measure(%n. n)"
+recdef ack "measure(%m. m) <*lex*> measure(%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))"