Критерий полноты множества мультифункций в полном частичном ультраклоне ранга 2

The problem of completeness for some class of discrete functions is studied. Functions from this class map finite cartesian powers of a two-element set $E$ to the set of all subsets of $E$. Functions of this kind are called multifunctions of rank $2$. We proved a necessary and sufficient condition of completeness using some special notion of superposition for an arbitrary set of functions from a given class.