English

Asymptotic dimension for covers with controlled growth

Metric Geometry 2025-05-14 v1

Abstract

We prove various obstructions to the existence of regular maps (or coarse embeddings) between commonly studied spaces. For instance, there is no regular map (or coarse embedding) HnHn1×Y\mathbb H^n\to\mathbb H^{n-1}\times Y for n3n\geq 3, or (T3)n(T3)n1×Y(T_3)^n \to (T_3)^{n-1}\times Y whenever YY is a bounded degree graph with subexponential growth, where T3T_3 is the 33-regular tree. We also resolve a question of Benjamini-Schramm-Tim\'ar, proving that there is no regular map H2T3×Y\mathbb H^2 \to T_3 \times Y whenever YY is a bounded degree graph with at most polynomial growth, and no quasi-isometric embedding whenever YY has subexponential growth. Finally, we show that there is no regular map FnZFn1F^n\to \mathbb Z\wr F^{n-1} where FF is the free group on two generators. To prove these results, we introduce and study generalizations of asymptotic dimension which allow unbounded covers with controlled growth. For bounded degree graphs, these invariants are monotone with respect to regular maps (hence coarse embeddings).

Keywords

Cite

@article{arxiv.2303.01969,
  title  = {Asymptotic dimension for covers with controlled growth},
  author = {David Hume and John M. Mackay and Romain Tessera},
  journal= {arXiv preprint arXiv:2303.01969},
  year   = {2025}
}

Comments

39 pages

R2 v1 2026-06-28T08:59:43.771Z