English

Perfect but not generating Delaunay polytopes

Combinatorics 2009-11-11 v3 Geometric Topology

Abstract

In his seminal 1951 paper "Extreme forms" Coxeter \cite{cox51} observed that for n9n \ge 9 one can add vectors to the perfect lattice \sfA9\sfA_9 so that the resulting perfect lattice, called \sfA92\sfA_9^2 by Coxeter, has exactly the same set of minimal vectors. An inhomogeneous analog of the notion of perfect lattice is that of a lattice with a perfect Delaunay polytope: the vertices of a perfect Delaunay polytope are the analogs of minimal vectors in a perfect lattice. We find a new infinite series P(n,s)P(n,s) for s2s\geq 2 and n+14sn+1\geq 4s of nn-dimensional perfect Delaunay polytopes. A remarkable property of this series is that for certain values of ss and all n13n \ge 13 one can add points to the integer affine span of P(n,s)P(n,s) in such a way that P(n,s)P(n,s) remains a perfect Delaunay polytope in the new lattice. Thus, we have constructed an inhomogeneous analog of the remarkable relationship between \sfA9\sfA_9 and \sfA92\sfA_9^2.

Keywords

Cite

@article{arxiv.0905.4555,
  title  = {Perfect but not generating Delaunay polytopes},
  author = {Mathieu Dutour Sikiric and Konstantin Rybnikov},
  journal= {arXiv preprint arXiv:0905.4555},
  year   = {2009}
}

Comments

8 pages

R2 v1 2026-06-21T13:06:56.397Z