English

Many equiprojective polytopes

Metric Geometry 2025-10-06 v2 Combinatorics

Abstract

A 33-dimensional polytope PP is kk-equiprojective when the projection of PP along any line that is not parallel to a facet of PP is a polygon with kk vertices. In 1968, Geoffrey Shephard asked for a description of all equiprojective polytopes. It has been shown recently that the number of combinatorial types of kk-equiprojective polytopes is at least linear as a function of kk. Here, it is shown that there are at least k3k/2+o(k)k^{3k/2+o(k)} such combinatorial types as kk goes to infinity. This relies on the Goodman--Pollack lower bound on the number of order types and on new constructions of equiprojective polytopes via Minkowski sums.

Keywords

Cite

@article{arxiv.2307.11366,
  title  = {Many equiprojective polytopes},
  author = {Théophile Buffière and Lionel Pournin},
  journal= {arXiv preprint arXiv:2307.11366},
  year   = {2025}
}

Comments

25 pages, 5 figures