“…The problem of essential selfadjointness of the Dirac operator, which is a special case of our differential operator, has many references; see, for example, [1, 4, 14, 16, 26, 28, 32] and papers quoted therein. Usually (see, [1,14,16,32]) functions bounded at infinity but with poles in R m are considered. The proof of selfadjointness of A relies in such cases on showing that A 1 u d A 0 u + d u (u ∈ (C ∞ 0 (R m )) k ) for some d ∈ [0, 1), d 0 (for example, [16, Problem V.5.11]) or d ∈ [0, 1), d = 0 (for example, [14]).…”