src/HOL/Isar_examples/Puzzle.thy
changeset 12997 80dec7322a8c
parent 10436 98c421dd5972
child 16417 9bc16273c2d4
     1.1 --- a/src/HOL/Isar_examples/Puzzle.thy	Fri Mar 01 16:24:43 2002 +0100
     1.2 +++ b/src/HOL/Isar_examples/Puzzle.thy	Fri Mar 01 16:59:48 2002 +0100
     1.3 @@ -24,8 +24,7 @@
     1.4    show ge: "!!n. n <= f n"
     1.5    proof -
     1.6      fix k show "!!n. k == f n ==> n <= k" (is "PROP ?P k")
     1.7 -    proof (induct k
     1.8 -        rule: nat_less_induct [rule_format])
     1.9 +    proof (induct k rule: less_induct)
    1.10        fix k assume hyp: "!!m. m < k ==> PROP ?P m"
    1.11        fix n assume k_def: "k == f n"
    1.12        show "n <= k"