Local and 2-Local Lie Derivations of Operator Algebras on Banach Spaces

Let X be a Banach space of dimension > 2. We show that every local Lie derivation of B(X) is a Lie derivation, and that a map of B(X) is a 2-local Lie derivation if and only if it has the form ${A \mapsto AT - TA + \psi(A)}$ A ? A T - T A + ψ ( A ) , where ${T \in B(X)}$ T ∈ B ( X ) and ψ is a homogeneous map from B(X) into ${\mathbb{F}I}$ F I satisfying ${\psi(A + B) = \psi(A)}$ ψ ( A + B ) = ψ ( A ) for ${A, B \in B(X)}$ A , B ∈ B ( X ) with B being a sum of commutators.