diff -r 449e1a1bb7a8 -r d848c6693185 doc-src/TutorialI/Inductive/advanced-examples.tex --- a/doc-src/TutorialI/Inductive/advanced-examples.tex Fri Feb 16 00:36:21 2001 +0100 +++ b/doc-src/TutorialI/Inductive/advanced-examples.tex Fri Feb 16 06:46:20 2001 +0100 @@ -65,7 +65,7 @@ enlarging the set of function symbols enlarges the set of ground terms. The proof is a trivial rule induction. First we use the \isa{clarify} method to assume the existence of an element of -\isa{terms~F}. (We could have used \isa{intro subsetI}.) We then +\isa{gterms~F}. (We could have used \isa{intro subsetI}.) We then apply rule induction. Here is the resulting subgoal: \begin{isabelle} \ 1.\ \isasymAnd x\ args\ f.\isanewline @@ -96,14 +96,14 @@ Recall that \isa{even} is the minimal set closed under these two rules: \begin{isabelle} 0\ \isasymin \ even\isanewline -n\ \isasymin \ even\ \isasymLongrightarrow \ (Suc\ (Suc\ n))\ \isasymin +n\ \isasymin \ even\ \isasymLongrightarrow \ Suc\ (Suc\ n)\ \isasymin \ even \end{isabelle} Minimality means that \isa{even} contains only the elements that these rules force it to contain. If we are told that \isa{a} belongs to \isa{even} then there are only two possibilities. Either \isa{a} is \isa{0} -or else \isa{a} has the form \isa{Suc(Suc~n)}, for an arbitrary \isa{n} +or else \isa{a} has the form \isa{Suc(Suc~n)}, for some suitable \isa{n} that belongs to \isa{even}. That is the gist of the \isa{cases} rule, which Isabelle proves for us when it accepts an inductive definition: