Dynamics of metrics in measure spaces and scaling entropy

A. M. Vershik, G. A. Veprev, P. B. Zatitskii

Published 2023-11-24Version 1

This survey is dedicated to a new direction in the theory of dynamical systems: the dynamics of metrics in measure spaces and new (catalytic) invariants of transformations with invariant measure. A space equipped with a measure and a metric naturally consistent with each other (a metric triple, or an $mm$-space) automatically determines the notion of its entropy class, thus allowing one to construct a theory of scaling entropy for dynamical systems with invariant measure, which is different and more general compared to the Shannon-Kolmogorov theory. This possibility was hinted at by Shannon himself, but the hint went unnoticed. The classification of metric triples in terms of matrix distributions presented in this paper was proposed by M. Gromov and A. Vershik. We describe some corollaries obtained by applying this theory. A brief overview of the paper is presented in the first chapter.