mekso operator: power set - produces the set of all subsets of set A that are of (any) size (that is) b [a nonnegative integer or transfinite/infinite number]

Possibly also could be used as a nonlogical "connective" of sorts. For accessing more than one cardinality in b, use modifiers ("less than"/"greater than") or vague numbers; default: «su'e ro», which outputs the set of all subsets of A; thus, the unary operator is just the standard power set operator.