Birkhoff-James classification of norm's properties

التفاصيل البيبلوغرافية
العنوان: Birkhoff-James classification of norm's properties
المؤلفون: Guterman, Alexander, Kuzma, Bojan, Singla, Sushil, Zhilina, Svetlana
سنة النشر: 2024
المجموعة: Mathematics
مصطلحات موضوعية: Mathematics - Functional Analysis, 46B20, 05C63
الوصف: For an arbitrary normed space $\mathcal X$ over a field $\mathbb F \in \{ \mathbb R, \mathbb C \}$, we define the directed graph $\Gamma(\mathcal X)$ induced by Birkhoff-James orthogonality on the projective space $\mathbb P(\mathcal X)$, and also its nonprojective counterpart $\Gamma_0(\mathcal X)$. We show that, in finite-dimensional normed spaces, $\Gamma(\mathcal X)$ carries all the information about the dimension, smooth points, and norm's maximal faces. It also allows to determine whether the norm is a supremum norm or not, and thus classifies finite-dimensional abelian $C^\ast$-algebras among other normed spaces. We further establish the necessary and sufficient conditions under which the graph $\Gamma_0(\mathcal{R})$ of a (real or complex) Radon plane $\mathcal{R}$ is isomorphic to the graph $\Gamma_0(\mathbb F^2, \|\cdot\|_2)$ of the two-dimensional Hilbert space and construct examples of such nonsmooth Radon planes.
Comment: Accepted for publications in AOT in The Special Issue Dedicated to Professor Chi-Kwong Li
نوع الوثيقة: Working Paper
الوصول الحر: http://arxiv.org/abs/2402.13416Test
رقم الانضمام: edsarx.2402.13416
قاعدة البيانات: arXiv