Diversity of Lipschitz-free spaces over countable complete discrete metric spaces
Abstract
We show that there are uncountably many mutually non-isomorphic Lipschitz-free spaces over countable, complete, discrete metric spaces. Also there is a countable, complete, discrete metric space whose free space does not embed into the free space of any uniformly discrete metric space. This enhanced diversity is a consequence of the fact that the dentability index presents a highly non-binary behavior when assigned to the free spaces of metric spaces outside of the oppressive confines of compact purely 1-unrectifiable spaces. Indeed, the cardinality of countable, complete, discrete is uncountable while infinite, compact, purely 1-unrectifiable. Similar barrier is observed for uniformly discrete metric spaces as higher values of the dentability index are excluded for their free spaces: infinite, uniformly discrete.
Cite
@article{arxiv.2505.19891,
title = {Diversity of Lipschitz-free spaces over countable complete discrete metric spaces},
author = {Estelle Basset and Gilles Lancien and Antonín Procházka},
journal= {arXiv preprint arXiv:2505.19891},
year = {2025}
}