Generalized geometric constants related to Birkhoff orthogonality in Banach spaces

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Authors: Junxiang Qi, Qian Li, Zhouping Yin, Qi Liu, Jiaye Bi, Yuankang Fu, Yongjin Li
Cited by: 0

Abstract

In this paper, based on Birkhoff orthogonality, we introduce two geometric constants $\boldsymbol{A}_{\boldsymbol{t}}^{\boldsymbol{B}}(\boldsymbol{X})$ and $\boldsymbol{D}_{\boldsymbol{t}}^{\boldsymbol{B}}(\boldsymbol{X})$ in Banach spaces, which generalize the skew geometric constants related to Birkhoff orthogonality. We systematically investigate the basic properties of the two constants, including their upper and lower bounds, and establish the equivalent characterizations for Banach spaces being uniformly non-square. Additionally, we explore the relationship between $\boldsymbol{D}_{\boldsymbol{t}}^{\boldsymbol{B}}(\boldsymbol{X})$ and the modulus of convexity $\boldsymbolδ_{\boldsymbol{X}}(\boldsymbol{\varepsilon})$. Finally, we explore several applications of the two newly proposed geometric constants.

Fields of Study & Subjects

Advanced Banach Space Theory Mathematical Inequalities and Applications Optimization and Variational Analysis

Publication details

Journal / source
arXiv (Cornell University)
Publication date
15 February 2026
Language
EN
Document type
Preprint