$\forall$$i$:Id, $k$:\{$k$:Knd$\mid$ $\uparrow$hasloc($k$;$i$)\} , $V$, $T$:Type, $f$:($V$$\rightarrow$($T$ + Top)).
\\[0ex]ma{-}trivial{-}interface($i$;$k$;$V$;$f$) $\in$ MaInterface($T$)