\begin{tabbing}
scheme{-}compatible($A$;$B$)
\\[0ex]$\,\equiv$$_{\mbox{\scriptsize def}}$$\;\;$\=let ${\it na}$,${\it La}$,${\it Ra}$ = $A$ in \+
\\[0ex]let ${\it nb}$,${\it Lb}$,${\it Rb}$ = $B$ in 
\\[0ex]$\forall$${\it nmr\_a}$:Namer(${\it na}$;${\it La}$), ${\it nmr\_b}$:Namer(${\it nb}$;${\it Lb}$).
\\[0ex]namer{-}disjoint(${\it na}$;${\it nb}$;${\it nmr\_a}$;${\it nmr\_b}$) $\Rightarrow$ ${\it Ra}$(${\it nmr\_a}$) $\parallel$ ${\it Rb}$(${\it nmr\_b}$)
\-
\end{tabbing}