数学物理学报(英文版) ›› 2022, Vol. 42 ›› Issue (2): 789-794.doi: 10.1007/s10473-022-0223-8

• 论文 • 上一篇    下一篇

MAPS PRESERVING THE NORM OF THE POSITIVE SUM IN Lp SPACES

郝晶晶1, 董云柏2, 李磊3   

  1. 1. School of Mathematical Sciences, Nankai University, Tianjin 300071, China;
    2. Hubei Key Laboratory of Applied Mathematics, Faculty of Mathematics and Statistics, Hubei University, Wuhan 430062, China;
    3. School of Mathematical Sciences and LPMC, Nankai University, Tianjin 300071, China
  • 收稿日期:2020-12-24 修回日期:2021-03-11 出版日期:2022-04-25 发布日期:2022-04-22
  • 通讯作者: Yunbai DONG,E-mail:baiyunmu301@126.com E-mail:baiyunmu301@126.com
  • 作者简介:Jingjing HAO,E-mail:271869637@qq.com;Lei LI,E-mail:leilee@nankai.edu.cn
  • 基金资助:
    Dong is partially supported by the NSF of China (11671314). Li is partially supported by the NSF of China (12171251).

MAPS PRESERVING THE NORM OF THE POSITIVE SUM IN Lp SPACES

Jingjing HAO1, Yunbai DONG2, Lei LI3   

  1. 1. School of Mathematical Sciences, Nankai University, Tianjin 300071, China;
    2. Hubei Key Laboratory of Applied Mathematics, Faculty of Mathematics and Statistics, Hubei University, Wuhan 430062, China;
    3. School of Mathematical Sciences and LPMC, Nankai University, Tianjin 300071, China
  • Received:2020-12-24 Revised:2021-03-11 Online:2022-04-25 Published:2022-04-22
  • Supported by:
    Dong is partially supported by the NSF of China (11671314). Li is partially supported by the NSF of China (12171251).

摘要: {For $1 < p < \infty$, let $S(L_p)_+$ be the set of positive elements in $L_p$ with norm one. Assume that $V_0: S(L_p(\Omega_1))_{+}\to S(L_p(\Omega_2))_{+}$ is a surjective norm-additive map; that is, \[\|V_0(x)+V_0(y)\|=\|x+y\|,\quad\forall\,x, y\in S(L_p(\Omega_1 ))_{+}.\] In this paper, we show that $V_0$ can be extended to an isometry from $L_p(\Omega_1)$ onto $L_p(\Omega_2)$.

关键词: Norm-additive mappings, positive cones, Lp spaces

Abstract: {For $1 < p < \infty$, let $S(L_p)_+$ be the set of positive elements in $L_p$ with norm one. Assume that $V_0: S(L_p(\Omega_1))_{+}\to S(L_p(\Omega_2))_{+}$ is a surjective norm-additive map; that is, \[\|V_0(x)+V_0(y)\|=\|x+y\|,\quad\forall\,x, y\in S(L_p(\Omega_1 ))_{+}.\] In this paper, we show that $V_0$ can be extended to an isometry from $L_p(\Omega_1)$ onto $L_p(\Omega_2)$.

Key words: Norm-additive mappings, positive cones, Lp spaces

中图分类号: 

  • 46E30