MINIMAL WIDTHSS AND ORTHOGONALITY TYPES  

作　　者：Chan HE Horst MARTINI Senlin WU 何婵;Horst MARTINI;吴森林(School of Mathematics,North University of China,Taiyuan,030051,China;Fakultät für Mathematik,Technische Universität Chemnitz,09107,Chemnitz,Germany)

机构地区：[1]School of Mathematics,North University of China,Taiyuan,030051,China [2]Fakultät für Mathematik,Technische Universität Chemnitz,09107,Chemnitz,Germany

出　　处：《Acta Mathematica Scientia》2025年第1期27-39,共13页数学物理学报(B辑英文版)

基　　金：supported by the National Natural Science Foundation of China(12071444,12201581);the Fundamental Research Program of Shanxi Province of China(202103021223191).

摘　　要：The minimal widths of three bounded subsets of the unit sphere associated to a unit vector in a normed linear space are studied,and three related geometric constants are introduced.New characterizations of inner product spaces are also presented.From the perspective of minimal width,strongε-symmetry of Birkhoff orthogonality is introduced,and its relation toε-symmetry of Birkhoff orthogonality is shown.Unlike most of the existing parameters of the underlying space,these new constants are full dimensional in nature.

关 键 词：Birkhoff orthogonality isosceles orthogonality minimal width Singer orthogonality strong e-symmetry of Birkhoff orthogonality width function 

分 类 号：O17[理学—数学]