\begin{tabbing}
es{-}real{-}and\=\{i:l\}\+
\\[0ex]($P$; $Q$; $X$; $Y$; $p$)
\-\\[0ex]$\,\equiv$$_{\mbox{\scriptsize def}}$$\;\;$$<$($X$.1) $\oplus$ ($Y$.1), TERMOF\{R{-}and{-}rule:ObjectId, 1:l, i:l\}(($X$.1),$Y$.1,$P$,$Q$,$X$.2,$Y$.2,$p$)$>$
\end{tabbing}