$\forall$${\it es}$:ES, ${\it e'}$:E, $P$:(\{$e$:E$\mid$ loc($e$) = loc(${\it e'}$) $\in$ Id\} $\rightarrow\mathbb{P}$). ($\forall$$e$$<$${\it e'}$. $P$($e$)) $\in$ $\mathbb{P}$