On extreme points and representer theorems for the Lipschitz unit ball on finite metric spaces

Fuente: arXiv
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Main Authors: Bredies, Kristian, Rodriguez, Jonathan Chirinos, Naldi, Emanuele
Format: Preprint
Published: 2023
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author Bredies, Kristian
Rodriguez, Jonathan Chirinos
Naldi, Emanuele
author_facet Bredies, Kristian
Rodriguez, Jonathan Chirinos
Naldi, Emanuele
contents In this note, we provide a characterization for the set of extreme points of the Lipschitz unit ball in a specific vectorial setting. While the analysis of the case of real-valued functions is covered extensively in the literature, no information about the vectorial case has been provided up to date. Here, we aim at partially filling this gap by considering functions mapping from a finite metric space to a strictly convex Banach space that satisfy the Lipschitz condition. As a consequence, we present a representer theorem for such functions. In this setting, the number of extreme points needed to express any point inside the ball is independent of the dimension, improving the classical result from Carathéodory.
format Preprint
id arxiv_https___arxiv_org_abs_2304_14039
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle On extreme points and representer theorems for the Lipschitz unit ball on finite metric spaces
Bredies, Kristian
Rodriguez, Jonathan Chirinos
Naldi, Emanuele
Functional Analysis
46A55 (Primary) 46N10, 52A05 (Secondary)
In this note, we provide a characterization for the set of extreme points of the Lipschitz unit ball in a specific vectorial setting. While the analysis of the case of real-valued functions is covered extensively in the literature, no information about the vectorial case has been provided up to date. Here, we aim at partially filling this gap by considering functions mapping from a finite metric space to a strictly convex Banach space that satisfy the Lipschitz condition. As a consequence, we present a representer theorem for such functions. In this setting, the number of extreme points needed to express any point inside the ball is independent of the dimension, improving the classical result from Carathéodory.
title On extreme points and representer theorems for the Lipschitz unit ball on finite metric spaces
topic Functional Analysis
46A55 (Primary) 46N10, 52A05 (Secondary)
url https://arxiv.org/abs/2304.14039