设B(H)是复Hilbert空间H上的有界线性算子全体且dim(H)≥2,证明了当H是有限维时,B(H)上的线性映射φ保持算子Jordan积非零投影性的充分必要条件是存在B(H)中的酉算子U以及常数λ∈{-1,1},使得φ(X)=λUXU*,X∈B(H)或φ(X)=λUXTU*,X∈B(H);同时得到了有界线性满射φ保持算子Jordan积非零投影性的特征.
Let B(H) be the set of all bounded linear operators on a complex Hilbert space H with dim(H)≥2.It is proved that a linear map φ on B(H) preserves the non-zero projection property of Jordan products of two operators if and only if there is a unitary operator U in B(H) and λ∈{-1,1},such that φ(X)=λUXU*,X∈B(H) or φ(X)=λUXTU*,X∈B(H).At the same time,related results for bounded linear surjective maps preserving non-zero projection property of Jordan product property of operators are also obtained