设X是维数大于1的Banach空间且ξ≠±1。 如果对任意的A,B∈B(X)且ABA=A, 线性映射φ:B(X)→B(X)满足 φ([A,B]ξ)=[φ(A),B]ξ+[A,φ(B)]ξ, 则φ是导子。
Let X be a Banach space with dim X〉1, and ξ≠±1. In this paper, we show that if a linear map φ:B(X)→B(X) satisfies φ([A,B]ξ)=[φ(A),B]ξ+[A,φ(B)]ξ for all A,B∈B(X) with ABA=A, then φ is a derivation.