$M$.aframe($k$ affects $x$)
\\[0ex]$\,\equiv$$_{\mbox{\scriptsize def}}$$\;\;$$L$ != 1of(2of(2of(2of(2of(2of(2of(2of(2of($M$)))))))))($k$) $\Rightarrow$ deq{-}member(IdDeq;$x$;$L$)