$\forall$$T$:Type, $L_{1}$, $L_{2}$, $L$:$T$ List. disjoint\_sublists($T$;$L_{1}$;$L_{2}$;$L$) $\Rightarrow$ \{$L_{1}$ $\subseteq$ $L$ \& $L_{2}$ $\subseteq$ $L$\}