Maximal δ-separated sets in separable metric spaces and weak forms of choice
arXiv:2405.10466 · doi:10.1017/jsl.2025.10176
Abstract
We show that the statement ``In every separable pseudometric space there is a maximal non-strictly δ-separated set.'' implies the axiom of choice for countable families of sets. This gives answers to a question of Dybowski and Górka in [M. Dybowski and P. Górka, The axiom of choice in metric measure spaces and maximal δ-separated sets, Archive for Mathematical Logic 62, 735-749, 2023.]. We also prove several related results.