On subsets of $S^n$ whose $(n+1)$-point subsets are contained in open hemisheres
Group Theory
2012-08-27 v1 Combinatorics
Metric Geometry
Abstract
We investigate the nature of subsets of spheres which satisfy a tameness condition associated with the Bieri-Groves conjecture on cohomological finiteness conditions for metabelian groups. We find that there is a natural polyhedrality in a crucial special case. In the case of the two dimensional sphere we establish a strong polyhedrality condition for certain open sets which are maximal subject to satisfying the tameness condition that subsets of three or fewer points are contained in open hemispheres. Many examples are included.
Keywords
Cite
@article{arxiv.1208.5041,
title = {On subsets of $S^n$ whose $(n+1)$-point subsets are contained in open hemisheres},
author = {Robert Bieri and Peter Kropholler and Brendan Owens},
journal= {arXiv preprint arXiv:1208.5041},
year = {2012}
}