“…For ZK equation there is a lot of literature, devoted to the initial value and initial-boundary value problems, where the variable y is considered on the whole line (see, for example, bibliography in [10,11] and recent papers [13,23]). In particular, global well-posedness in Sobolev spaces H k of arbitrary large regularity to the initial value problem and the initial-boundary value problem, posed on R 2 + = {(x, y) : x > 0} and (0, 1) × R , was established (see, for example, [6,7]).…”