doc-src/TutorialI/Recdef/document/Induction.tex

 are invented by Isabelle and have nothing to do with the names in the
 definition of \isa{sep}.
 
 In general, the format of invoking recursion induction is
 \begin{quote}
-\isacommand{apply}\isa{{\isacharparenleft}induct{\isacharunderscore}tac\ }$x@1 \dots x@n$ \isa{rule{\isacharcolon}} $f$\isa{{\isachardot}induct{\isacharparenright}}
+\isacommand{apply}\isa{{\isacharparenleft}induct{\isacharunderscore}tac}$x@1 \dots x@n$ \isa{rule{\isacharcolon}} $f$\isa{{\isachardot}induct{\isacharparenright}}
 \end{quote}\index{*induct_tac}%
 where $x@1~\dots~x@n$ is a list of free variables in the subgoal and $f$ the
 name of a function that takes an $n$-tuple. Usually the subgoal will
 contain the term $f(x@1,\dots,x@n)$ but this need not be the case. The
 induction rules do not mention $f$ at all. For example \isa{sep{\isachardot}induct}