English

Sets in Almost General Position

Combinatorics 2016-01-28 v1

Abstract

Erd\H{o}s asked the following question: given nn points in the plane in almost general position (no 4 collinear), how large a set can we guarantee to find that is in general position (no 3 collinear)? F\"uredi constructed a set of nn points in almost general position with no more than o(n)o(n) points in general position. Cardinal, T\'oth and Wood extended this result to R3\mathbb{R}^3, finding sets of nn points with no 5 on a plane whose subsets with no 4 points on a plane have size o(n)o(n), and asked the question for higher dimensions: for given nn, is it still true that the largest subset in general position we can guarantee to find has size o(n)o(n)? We answer their question for all dd and derive improved bounds for certain dimensions.

Keywords

Cite

@article{arxiv.1601.07206,
  title  = {Sets in Almost General Position},
  author = {Luka Milićević},
  journal= {arXiv preprint arXiv:1601.07206},
  year   = {2016}
}

Comments

20 pages, no figures

R2 v1 2026-06-22T12:37:25.313Z