Generalized biderivations of nest algebras

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