$\forall$${\it ea}$, ${\it eb}$:$\mathbb{N}$ List, $x$:$\mathbb{B}$+Unit, $f$, $g$:($\mathbb{N}\rightarrow\mathbb{B}$). combine{-}halt{-}info(${\it ea}$;${\it eb}$;$f$;$g$;$x$) $\in$ $\mathbb{B}$+Unit