The smallest mono-unstable, homogeneous convex polyhedron has at least 7 vertices
Fuente:
arXiv
Saved in:
| Main Authors: | , , , |
|---|---|
| Format: | Preprint |
| Published: |
2024
|
| Subjects: | |
| Online Access: | |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1866911905882308608 |
|---|---|
| author | Bozóki, Sándor Domokos, Gábor Papp, Dávid Regős, Krisztina |
| author_facet | Bozóki, Sándor Domokos, Gábor Papp, Dávid Regős, Krisztina |
| contents | We prove that every homogeneous convex polyhedron with only one unstable equilibrium (known as a mono-unstable convex polyhedron) has at least $7$ vertices. Although it has been long known that no mono-unstable tetrahedra exist, and mono-unstable polyhedra with as few as $18$ vertices and faces have been constructed, this is the first nontrivial lower bound on the number of vertices for a mono-unstable polyhedron.
There are two main ingredients in the proof. We first establish two types of relationships, both expressible as (non-convex) quadratic inequalities, that the coordinates of the vertices of a mono-unstable convex polyhedron must satisfy, taking into account the combinatorial structure of the polyhedron. Then we use numerical semidefinite optimization algorithms to compute easily and independently verifiable, rigorous certificates that the resulting systems of quadratic inequalities (5943 in total) are indeed inconsistent in each case. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2401_17906 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | The smallest mono-unstable, homogeneous convex polyhedron has at least 7 vertices Bozóki, Sándor Domokos, Gábor Papp, Dávid Regős, Krisztina Metric Geometry 52B10 (Primary) 90C22, 37C20, 52A38 (Secondary) We prove that every homogeneous convex polyhedron with only one unstable equilibrium (known as a mono-unstable convex polyhedron) has at least $7$ vertices. Although it has been long known that no mono-unstable tetrahedra exist, and mono-unstable polyhedra with as few as $18$ vertices and faces have been constructed, this is the first nontrivial lower bound on the number of vertices for a mono-unstable polyhedron. There are two main ingredients in the proof. We first establish two types of relationships, both expressible as (non-convex) quadratic inequalities, that the coordinates of the vertices of a mono-unstable convex polyhedron must satisfy, taking into account the combinatorial structure of the polyhedron. Then we use numerical semidefinite optimization algorithms to compute easily and independently verifiable, rigorous certificates that the resulting systems of quadratic inequalities (5943 in total) are indeed inconsistent in each case. |
| title | The smallest mono-unstable, homogeneous convex polyhedron has at least 7 vertices |
| topic | Metric Geometry 52B10 (Primary) 90C22, 37C20, 52A38 (Secondary) |
| url | https://arxiv.org/abs/2401.17906 |