Adding a point to configurations in closed balls
Geometric Topology
2019-05-09 v2
Abstract
We answer the question of when a new point can be added in a continuous way to configurations of distinct points in a closed ball of arbitrary dimension. We show that this is possible given an ordered configuration of points if and only if . On the other hand, when the points are not ordered and the dimension of the ball is at least 2, a point can be added continuously if and only if . These results generalize the Brouwer fixed-point theorem, which gives the negative answer when . We also show that when , there is a unique solution to both the ordered and unordered versions of the problem up to homotopy.
Cite
@article{arxiv.1809.06946,
title = {Adding a point to configurations in closed balls},
author = {Lei Chen and Nir Gadish and Justin Lanier},
journal= {arXiv preprint arXiv:1809.06946},
year = {2019}
}
Comments
6 pages; simplified proof of Theorem B and added proof of uniqueness for the case $n=2$ as Theorem C