“…In the theory of Toeplitz operators on higher dimensional polydisks, it has been known that the zero and compact properties often coincide, especially when pluriharmonic symbols are considered, as one can see from results in [8], [11], [15], [17] and [24]. For example, we have the following characterizations of compact (semi)commutators with pluriharmonic symbols u, v ∈ ph ∞ : ([15] and [8]);…”