diff -r 449e1a1bb7a8 -r d848c6693185 doc-src/TutorialI/Inductive/Star.thy --- a/doc-src/TutorialI/Inductive/Star.thy Fri Feb 16 00:36:21 2001 +0100 +++ b/doc-src/TutorialI/Inductive/Star.thy Fri Feb 16 06:46:20 2001 +0100 @@ -8,7 +8,7 @@ Relations too can be defined inductively, since they are just sets of pairs. A perfect example is the function that maps a relation to its reflexive transitive closure. This concept was already -introduced in \S\ref{sec:Relations}, where the operator @{text"^*"} was +introduced in \S\ref{sec:Relations}, where the operator @{text"\<^sup>*"} was defined as a least fixed point because inductive definitions were not yet available. But now they are: *} @@ -97,7 +97,7 @@ \end{quote} A similar heuristic for other kinds of inductions is formulated in \S\ref{sec:ind-var-in-prems}. The @{text rule_format} directive turns -@{text"\"} back into @{text"\"}. Thus in the end we obtain the original +@{text"\"} back into @{text"\"}: in the end we obtain the original statement of our lemma. *} @@ -148,8 +148,7 @@ contains only two rules, and the single step rule is simpler than transitivity. As a consequence, @{thm[source]rtc.induct} is simpler than @{thm[source]rtc2.induct}. Since inductive proofs are hard enough -anyway, we should -certainly pick the simplest induction schema available. +anyway, we should always pick the simplest induction schema available. Hence @{term rtc} is the definition of choice. \begin{exercise}\label{ex:converse-rtc-step}