--- a/doc-src/TutorialI/Recdef/document/Nested1.tex Thu Aug 09 10:17:45 2001 +0200
+++ b/doc-src/TutorialI/Recdef/document/Nested1.tex Thu Aug 09 18:12:15 2001 +0200
@@ -27,15 +27,15 @@
where \isa{set} returns the set of elements of a list
and \isa{term{\isacharunderscore}list{\isacharunderscore}size\ {\isacharcolon}{\isacharcolon}\ term\ list\ {\isasymRightarrow}\ nat} is an auxiliary
function automatically defined by Isabelle
-(while processing the declaration of \isa{term}). First we have to understand why the
-recursive call of \isa{trev} underneath \isa{map} leads to the above
-condition. The reason is that \isacommand{recdef} ``knows'' that \isa{map}
+(while processing the declaration of \isa{term}). Why does the
+recursive call of \isa{trev} lead to this
+condition? Because \isacommand{recdef} knows that \isa{map}
will apply \isa{trev} only to elements of \isa{ts}. Thus the
condition expresses that the size of the argument \isa{t\ {\isasymin}\ set\ ts} of any
recursive call of \isa{trev} is strictly less than \isa{size\ {\isacharparenleft}App\ f\ ts{\isacharparenright}},
which equals \isa{Suc\ {\isacharparenleft}term{\isacharunderscore}list{\isacharunderscore}size\ ts{\isacharparenright}}. We will now prove the termination condition and
continue with our definition. Below we return to the question of how
-\isacommand{recdef} ``knows'' about \isa{map}.%
+\isacommand{recdef} knows about \isa{map}.%
\end{isamarkuptext}%
\end{isabellebody}%
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