Eccentric $p-$summing Lipschitz operators and integral inequalities on metric spaces and graphs

TL;DR

This paper introduces new notions of $p$-summability for Lipschitz operators on metric spaces and graphs, using alternative distance measures and integral inequalities, extending existing theories beyond linear frameworks.

Contribution

It proposes novel $p$-summability concepts for Lipschitz operators based on specific subsets of the Lipschitz dual space, with applications to metric graphs.

Findings

New $p$-summability notions characterized by integral dominations.

Application of theoretical results to analyze metric graphs.

Results on numerical indices satisfying summability and symmetry conditions.

Abstract

The extension of the concept of $p-$summability for linear operators to the context of Lipschitz operators on metric spaces has been extensively studied in recent years. This research primarily uses the linearization of the metric space $M$ afforded by the associated Arens-Eells space, along with the duality between $M$ and the metric dual space $M^\#$ defined by the real-valued Lipschitz functions on $M.$ However, alternative approaches to measuring distances between sequences of elements of metric spaces (essentially involved in the definition of $p-$summability) exist. One approach involves considering specific subsets of the unit ball of $M^\#$ for computing the distances between sequences, such as the real Lipschitz functions derived from evaluating the difference of the values of the metric from two points to a fixed point. We introduce new notions of summability for Lipschitz operators involving such functions, which are characterized by integral dominations for those operators. To show the applicability of our results, we use in the last part of the paper the theoretical tools obtained in the first part to the analysis of metric graphs. In particular, we show new results on the behavior of numerical indices defined on these graphs satisfying certain conditions of summability and symmetry.