\begin{tabbing}
f{-}event\=\{\$x:ut2\}\+
\\[0ex](${\it es}$; $L$; $e$)
\-\\[0ex]$\,\equiv$$_{\mbox{\scriptsize def}}$$\;\;$(loc($e$) $\in$ $L$) c$\wedge$ ($\neg$(es{-}after(${\it es}$; mkid\{\$x:ut2\}; $e$) = es{-}when(${\it es}$; mkid\{\$x:ut2\}; $e$)))
\end{tabbing}