How to avoid a compact set
Logic
2017-07-18 v2 Metric Geometry
Abstract
A first-order expansion of the -vector space structure on does not define every compact subset of every if and only if topological and Hausdorff dimension coincide on all closed definable sets. Equivalently, if is closed and the Hausdorff dimension of exceeds the topological dimension of , then every compact subset of every can be constructed from using finitely many boolean operations, cartesian products, and linear operations. The same statement fails when Hausdorff dimension is replaced by packing dimension.
Cite
@article{arxiv.1612.00785,
title = {How to avoid a compact set},
author = {Antongiulio Fornasiero and Philipp Hieronymi and Erik Walsberg},
journal= {arXiv preprint arXiv:1612.00785},
year = {2017}
}