agree\_on($T$;$x$.$P$($x$))($L_{1}$,$L_{2}$)
\\[0ex]$\,\equiv$$_{\mbox{\scriptsize def}}$$\;\;$$\parallel$$L_{1}$$\parallel$ $=$ $\parallel$$L_{2}$$\parallel$ $\in$ $\mathbb{Z}$ \& ($\forall$$i$:\{0..$\parallel$$L_{1}$$\parallel^{-}$\}. $P$($L_{1}$[$i$]) $\vee$ $P$($L_{2}$[$i$]) $\Rightarrow$ $L_{1}$[$i$] $=$ $L_{2}$[$i$] $\in$ $T$)