mekso operator: power set - produces the set of all subsets of set X_{1} that are of (any) size (that is) X_{2} [a nonnegative integer or transfinite/infinite number; default: su'o no].

Possibly also could be used as a nonlogical "connective" of sorts. For accessing more than one cardinality in X_{2}, use modifiers ("less than"/"greater than") or vague numbers; default: "su'o no", which outputs the set of all subsets of X_{1}; thus, the unary operator is just the standard power set operator.