Remark on unique continuation for higher powers of the Laplace operator

There are unique continuation results [2,5] for the differential inequality | Δ μ u ( x ) | ≤ | V ( x ) u ( x ) | , μ ∈ N , when V ∈ L loc d / 2 μ ( R d ) , d > 2 μ . In this paper we obtain a result for the case d = 2 μ .