On sets of points with few ordinary hyperplanes
Let $S$ be a set of $n$ points in the projective $d$-dimensional real space $\mathbb{RP}^d$ such that not all points of $S$ are contained in a single hyperplane and such that any subset of $d$ points of $S$ span a hyperplane. Let an ordinary hyperplane of $S$ be an hyperplane of $\mathbb{RP}^d$ cont...
| Autor: | |
|---|---|
| Tipo de documento: | dissertação |
| Data de publicação: | 2018 |
| País: | España |
| Recursos: | Universitat Politècnica de Catalunya (UPC) |
| Repositório: | UPCommons. Portal del coneixement obert de la UPC |
| Idioma: | inglês |
| OAI Identifier: | oai:upcommons.upc.edu:2117/124196 |
| Acesso em linha: | https://hdl.handle.net/2117/124196 |
| Access Level: | Acceso aberto |
| Palavra-chave: | Discrete geometry Discrete Geometry Incidence and Arrangement Problems Sylvester-Gallai-Type Problems Computational Geometry Combinatorial Geometry Geometria discreta Classificació AMS::52 Convex and discrete geometry::52C Discrete geometry Àrees temàtiques de la UPC::Matemàtiques i estadística::Geometria |
| Resumo: | Let $S$ be a set of $n$ points in the projective $d$-dimensional real space $\mathbb{RP}^d$ such that not all points of $S$ are contained in a single hyperplane and such that any subset of $d$ points of $S$ span a hyperplane. Let an ordinary hyperplane of $S$ be an hyperplane of $\mathbb{RP}^d$ containing exactly $d$ points of $S$. In this paper we study the minimum number of ordinary hyperplanes spanned by any set $S$ of $n$ points in $4$ dimensions, following the work of Ben Green and Terence Tao in the planar version of the problem, as well as the work of Simeon Ball in the $3$ dimensional case. We classify the sets of points in $4$ dimensions that span few ordinary hyperplanes, showing that if $S$ is a set spanning less than $Kn^3$ ordinary hyperplanes, for some $K = o(n^{\frac{1}{6}})$, then all but $O(K)$ points of $S$ must be contained in the intersection of $5$ linearly independent quadrics. |
|---|