English

Measurable tilings by abelian group actions

Dynamical Systems 2023-02-28 v2 Classical Analysis and ODEs Combinatorics Metric Geometry

Abstract

Let XX be a measure space with a measure-preserving action (g,x)gx(g,x) \mapsto g \cdot x of an abelian group GG. We consider the problem of understanding the structure of measurable tilings FA=XF \odot A = X of XX by a measurable tile AXA \subset X translated by a finite set FGF \subset G of shifts, thus the translates fAf \cdot A, fFf \in F partition XX up to null sets. Adapting arguments from previous literature, we establish a "dilation lemma" that asserts, roughly speaking, that FA=XF \odot A = X implies FrA=XF^r \odot A = X for a large family of integer dilations rr, and use this to establish a structure theorem for such tilings analogous to that established recently by the second and fourth authors. As applications of this theorem, we completely classify those random tilings of finitely generated abelian groups that are "factors of iid", and show that measurable tilings of a torus Td\mathbb{T}^d can always be continuously (in fact linearly) deformed into a tiling with rational shifts, with particularly strong results in the low-dimensional cases d=1,2d=1,2 (in particular resolving a conjecture of Conley, the first author, and Pikhurko in the d=1d=1 case).

Keywords

Cite

@article{arxiv.2203.01511,
  title  = {Measurable tilings by abelian group actions},
  author = {Jan Grebík and Rachel Greenfeld and Václav Rozhoň and Terence Tao},
  journal= {arXiv preprint arXiv:2203.01511},
  year   = {2023}
}

Comments

3 figures

R2 v1 2026-06-24T10:00:14.269Z