$\forall$$T$:Type, $L$:$T$ List, $P$, $Q_{1}$, $Q_{2}$:($\mathbb{N}$$_{\mbox{\scriptsize $<\parallel$$L$$\parallel$}}$$\rightarrow$Prop), $R$:($\mathbb{N}$$_{\mbox{\scriptsize $<\parallel$$L$$\parallel$}}$$\rightarrow\mathbb{N}$$_{\mbox{\scriptsize $<\parallel$$L$$\parallel$}}$$\rightarrow$Prop).
\\[0ex]($\forall$$i$:$\mathbb{N}$$_{\mbox{\scriptsize $<\parallel$$L$$\parallel$}}$. $Q_{2}$($i$) $\Rightarrow$ $Q_{1}$($i$)) $\Rightarrow$ causal\_order($L$;$R$;$P$;$Q_{1}$) $\Rightarrow$ causal\_order($L$;$R$;$P$;$Q_{2}$)