$\forall$$T$:Type, $X$:MaInterface($T$ + Top), ${\it es}$:ES.
\\[0ex]ma{-}interface{-}consistent(${\it es}$;$X$)
\\[0ex]$\Rightarrow$ ([[ma{-}interface{-}left($X$)]] = es{-}interface{-}left([[$X$]]) $\in$ AbsInterface($T$))