sublist\_occurence($T$;$L_{1}$;$L_{2}$;$f$) $\,\equiv$$_{\mbox{\scriptsize def}}$$\;\;$increasing($f$;$\parallel$$L_{1}$$\parallel$) \& ($\forall$$j$:$\mathbb{N}$$_{\mbox{\scriptsize $<\parallel$$L_{1}$$\parallel$}}$. $L_{1}$[$j$] $=$ $L_{2}$[$f$($j$)])