es{-}knows\{i:l\}(${\it poss}$; $R$; $P$; $e$) $\,\equiv$$_{\mbox{\scriptsize def}}$$\;\;$$\forall$${\it e'}$:possible{-}event\{i:l\}(${\it poss}$). $R$($e$,${\it e'}$) $\Rightarrow$ $P$(${\it e'}$)