$\forall$$p$:FinProbSpace, $n$:$\mathbb{N}$, $X$, $Y$:RandomVariable($p$;$n$), $x$:Outcome.
\\[0ex](0 $<$ $n$) $\Rightarrow$ rv{-}disjoint($p$;$n$;$X$;$Y$) $\Rightarrow$ rv{-}disjoint($p$;$n$ {-} 1;rv{-}shift($x$;$X$);rv{-}shift($x$;$Y$))