English

Optimality and uniqueness of the $D_4$ root system

Metric Geometry 2024-05-28 v2 Optimization and Control

Abstract

We prove that the D4D_4 root system (the set of vertices of the regular 2424-cell) is the unique optimal kissing configuration in R4\mathbb R^4, and is an optimal spherical code. For this, we use semidefinite programming to compute an exact optimal solution to the second level of the Lasserre hierarchy. We also improve the upper bound for the kissing number problem in R6\mathbb R^6 to 7777.

Cite

@article{arxiv.2404.18794,
  title  = {Optimality and uniqueness of the $D_4$ root system},
  author = {David de Laat and Nando M. Leijenhorst and Willem H. H. de Muinck Keizer},
  journal= {arXiv preprint arXiv:2404.18794},
  year   = {2024}
}
R2 v1 2026-06-28T16:09:57.330Z