article
Tverberg's Theorem and Graph Coloring
published
Alexander
Engström
author
Patrik
Noren
author 46870C74-F248-11E8-B48F-1D18A9856A87
CaUh
department
The topological Tverberg theorem has been generalized in several directions by setting extra restrictions on the Tverberg partitions. Restricted Tverberg partitions, defined by the idea that certain points cannot be in the same part, are encoded with graphs. When two points are adjacent in the graph, they are not in the same part. If the restrictions are too harsh, then the topological Tverberg theorem fails. The colored Tverberg theorem corresponds to graphs constructed as disjoint unions of small complete graphs. Hell studied the case of paths and cycles. In graph theory these partitions are usually viewed as graph colorings. As explored by Aharoni, Haxell, Meshulam and others there are fundamental connections between several notions of graph colorings and topological combinatorics. For ordinary graph colorings it is enough to require that the number of colors q satisfy q>Δ, where Δ is the maximal degree of the graph. It was proven by the first author using equivariant topology that if q>Δ 2 then the topological Tverberg theorem still works. It is conjectured that q>KΔ is also enough for some constant K, and in this paper we prove a fixed-parameter version of that conjecture. The required topological connectivity results are proven with shellability, which also strengthens some previous partial results where the topological connectivity was proven with the nerve lemma.
Springer2014
eng
Discrete & Computational Geometry10.1007/s00454-013-9556-3
511207 - 220
Engström, A., & Noren, P. (2014). Tverberg’s Theorem and Graph Coloring. <i>Discrete & Computational Geometry</i>. Springer. <a href="https://doi.org/10.1007/s00454-013-9556-3">https://doi.org/10.1007/s00454-013-9556-3</a>
Engström, Alexander, and Patrik Noren. “Tverberg’s Theorem and Graph Coloring.” <i>Discrete & Computational Geometry</i>. Springer, 2014. <a href="https://doi.org/10.1007/s00454-013-9556-3">https://doi.org/10.1007/s00454-013-9556-3</a>.
Engström A, Noren P. 2014. Tverberg’s Theorem and Graph Coloring. Discrete & Computational Geometry. 51(1), 207–220.
A. Engström, P. Noren, Discrete & Computational Geometry 51 (2014) 207–220.
Engström, Alexander, and Patrik Noren. “Tverberg’s Theorem and Graph Coloring.” <i>Discrete & Computational Geometry</i>, vol. 51, no. 1, Springer, 2014, pp. 207–20, doi:<a href="https://doi.org/10.1007/s00454-013-9556-3">10.1007/s00454-013-9556-3</a>.
A. Engström and P. Noren, “Tverberg’s Theorem and Graph Coloring,” <i>Discrete & Computational Geometry</i>, vol. 51, no. 1. Springer, pp. 207–220, 2014.
Engström A, Noren P. Tverberg’s Theorem and Graph Coloring. <i>Discrete & Computational Geometry</i>. 2014;51(1):207-220. doi:<a href="https://doi.org/10.1007/s00454-013-9556-3">10.1007/s00454-013-9556-3</a>
19112018-12-11T11:54:40Z2021-01-12T06:54:01Z