\begin{tabbing}
es{-}trans{-}state{-}from\{i:l\}(${\it es}$;${\it ks}$;$g$;$z$;$e_{1}$;$e_{2}$)
\\[0ex]$\,\equiv$$_{\mbox{\scriptsize def}}$$\;\;$list\_accum(\=$x$,$a$.let $k$,$s$,$v$ = $a$ in if deq{-}member(KindDeq;$k$;${\it ks}$)$\rightarrow$ $g$($k$,$s$,$v$,$x$) else $x$ fi;\+
\\[0ex]$z$;
\\[0ex]es{-}hist\{i:l\}(${\it es}$;$e_{1}$;$e_{2}$))
\-
\end{tabbing}