数学物理学报(英文版) ›› 1994, Vol. 14 ›› Issue (4): 475-478.

• 论文 • 上一篇    

A REMARK ON L1 SUBSPACES OF L1 (μ,X)

定光桂, 黄森忠   

  1. Department of Mathematics, Nankai University, Tianjin 300071, China
  • 收稿日期:1992-04-03 出版日期:1994-12-25 发布日期:1994-12-25

A REMARK ON L1 SUBSPACES OF L1 (μ,X)

Ding Guanggui, Huang Senzhong   

  1. Department of Mathematics, Nankai University, Tianjin 300071, China
  • Received:1992-04-03 Online:1994-12-25 Published:1994-12-25

摘要: Let (Ω, ,μ) be a measure space and (Xω)ωΩ a family of closed linear subspaces of some Banach space X. Let L1 (μ, (Xω)) be the linear subspace of the Bochner space L1 (μ,X) given by L1 (μ, (Xω)):={fL1 (μ,X):f(ω) ∈ Xω for all ωΩ}. Suppose that each Xω is of type p with constant 1 for some fixed p > 1. Two results are obtained:(1) If EL1 (μ, (Xω)) is isomorphic to some L1 space with constant less than 21-1/p, then there is a projection from L1 (μ,X) onto E. (2) If EL1 (μ, (Xω)) is a L1,λ space with λ small enough then E is complemented in L1 (μ, (Xω)). These results generalize early results of Dor[3], Alspach and Johnson[1].

Abstract: Let (Ω, ,μ) be a measure space and (Xω)ωΩ a family of closed linear subspaces of some Banach space X. Let L1 (μ, (Xω)) be the linear subspace of the Bochner space L1 (μ,X) given by L1 (μ, (Xω)):={fL1 (μ,X):f(ω) ∈ Xω for all ωΩ}. Suppose that each Xω is of type p with constant 1 for some fixed p > 1. Two results are obtained:(1) If EL1 (μ, (Xω)) is isomorphic to some L1 space with constant less than 21-1/p, then there is a projection from L1 (μ,X) onto E. (2) If EL1 (μ, (Xω)) is a L1,λ space with λ small enough then E is complemented in L1 (μ, (Xω)). These results generalize early results of Dor[3], Alspach and Johnson[1].