English

A geometric Hall-type theorem

Combinatorics 2016-02-02 v3

Abstract

We introduce a geometric generalization of Hall's marriage theorem. For any family F={X1,,Xm}F = \{X_1, \dots, X_m\} of finite sets in Rd\mathbb{R}^d, we give conditions under which it is possible to choose a point xiXix_i\in X_i for every 1im1\leq i \leq m in such a way that the points {x1,...,xm}Rd\{x_1,...,x_m\}\subset \mathbb{R}^d are in general position. We give two proofs, one elementary proof requiring slightly stronger conditions, and one proof using topological techniques in the spirit of Aharoni and Haxell's celebrated generalization of Hall's theorem.

Keywords

Cite

@article{arxiv.1412.6639,
  title  = {A geometric Hall-type theorem},
  author = {Andreas Holmsen and Leonardo Martinez-Sandoval and Luis Montejano},
  journal= {arXiv preprint arXiv:1412.6639},
  year   = {2016}
}
R2 v1 2026-06-22T07:39:14.277Z