$\forall$$A$,$B$:es\_realizer\{i:l\}.
\\[0ex]R{-}sub\{i:l\}($A$; $B$) $\Rightarrow$ ($\forall$${\it es}$:event\_system\{i:l\}. R{-}consistent($B$; ${\it es}$) $\Rightarrow$ R{-}consistent($A$; ${\it es}$))