diff -r 3c50a2cd6f00 -r ac8ca15c556c doc-src/TutorialI/Inductive/Even.thy --- a/doc-src/TutorialI/Inductive/Even.thy Sat Oct 06 00:02:46 2001 +0200 +++ b/doc-src/TutorialI/Inductive/Even.thy Mon Oct 08 12:13:34 2001 +0200 @@ -20,7 +20,7 @@ specified as \isa{intro!} Our first lemma states that numbers of the form $2\times k$ are even. *} -lemma two_times_even[intro!]: "#2*k \ even" +lemma two_times_even[intro!]: "2*k \ even" apply (induct "k") txt{* The first step is induction on the natural number \isa{k}, which leaves @@ -36,11 +36,11 @@ this equivalence is trivial using the lemma just proved, whose \isa{intro!} attribute ensures it will be applied automatically. *} -lemma dvd_imp_even: "#2 dvd n \ n \ even" +lemma dvd_imp_even: "2 dvd n \ n \ even" by (auto simp add: dvd_def) text{*our first rule induction!*} -lemma even_imp_dvd: "n \ even \ #2 dvd n" +lemma even_imp_dvd: "n \ even \ 2 dvd n" apply (erule even.induct) txt{* @{subgoals[display,indent=0,margin=65]} @@ -58,7 +58,7 @@ text{*no iff-attribute because we don't always want to use it*} -theorem even_iff_dvd: "(n \ even) = (#2 dvd n)" +theorem even_iff_dvd: "(n \ even) = (2 dvd n)" by (blast intro: dvd_imp_even even_imp_dvd) text{*this result ISN'T inductive...*} @@ -70,7 +70,7 @@ oops text{*...so we need an inductive lemma...*} -lemma even_imp_even_minus_2: "n \ even \ n-#2 \ even" +lemma even_imp_even_minus_2: "n \ even \ n - 2 \ even" apply (erule even.induct) txt{* @{subgoals[display,indent=0,margin=65]}