\begin{tabbing}
only $L$ sends on ($l$ with ${\it tg}$)
\\[0ex]$\,\equiv$$_{\mbox{\scriptsize def}}$$\;\;$ma\{\=$\otimes$;\+
\\[0ex]$\otimes$;
\\[0ex]$\otimes$;
\\[0ex]$\otimes$;
\\[0ex]$\otimes$;
\\[0ex]$\otimes$;
\\[0ex]$\otimes$;
\\[0ex]$<$$l$, ${\it tg}$$>$ : $L$;
\\[0ex]$\otimes$;
\\[0ex]$\otimes$;
\\[0ex]$\otimes$;
\\[0ex]$\otimes$\}
\-
\end{tabbing}