\begin{tabbing}
R{-}base{-}recognize($i$;${\it ds}$;$x$;$k$;$T$;${\it test}$)
\\[0ex]$\,\equiv$$_{\mbox{\scriptsize def}}$$\;\;$\=(@$i$ $x$ initially false$_{2}$:$\mathbb{B}$ $\oplus$ @$i$ only events in [$k$] change $x$:$\mathbb{B}$)\+
\\[0ex]$\oplus$ @$i$ effect $k$(v:$T$)  $x$ := $\lambda$$s$,$v$. if ${\it test}$($s$,$v$)$\rightarrow$ true$_{2}$ else $s$($x$) fi State($x$ : $\mathbb{B}$ $\oplus$ ${\it ds}$) v 
\-
\end{tabbing}