Multi$-$Level$-$Security $($MLS$)$

$$ Inthelatticeaboveis$($public$,\{$PER$\})$inrelationto$($private$,\{$ENG$\})?$ If yes, is it $($public$,\{$PER$\})($private$,\{$ENG$\})$ or vice versa? If No$,$ what is the relation? For which special security policy can we use such a relation?

$4$