English

A dichotomy for projections of planar sets

Metric Geometry 2012-03-06 v1 Combinatorics Dynamical Systems Number Theory

Abstract

We prove that most one-dimensional projections of a discrete subset of a plane are either dense in R (the real line), or form a discrete subset of R. More precisely, the set E of exceptional directions (for which the indicated dichotomy fails) is a meager subset of the unit circle T of Lebesgue measure 0. The set E however does not need to be small in the sense of Hausdorff dimension.

Keywords

Cite

@article{arxiv.1203.0669,
  title  = {A dichotomy for projections of planar sets},
  author = {Michael Boshernitzan},
  journal= {arXiv preprint arXiv:1203.0669},
  year   = {2012}
}

Comments

11 pages

R2 v1 2026-06-21T20:28:35.893Z