Generalized biderivations of nest algebras

Let N be a nest on a complex separable Hilbert space H, and τ(N) be the associated nest algebra. In this paper, we prove that every biderivation of τ(N) is an inner biderivation if and only if dim 0+ ≠ 1 or , and that every generalized biderivation of τ(N) is an inner generalized biderivation if dim 0+ ≠ 1 and .