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Thesis topic proposal
 
Jenő Szirmai
Ball packings, coverings and Dirichlet-Voronoi cells in Thurston geometries

THESIS TOPIC PROPOSAL

Institute: Budapest University of Technology and Economics
mathematics and computing
Doctoral School of Mathematics and Computer Sciences

Thesis supervisor: Jenő Szirmai
Location of studies (in Hungarian): Department of Geometry, Institute of Mathematics, BME
Abbreviation of location of studies: BME


Description of the research topic:

The classical sphere packing problems concern arrangements of non-overlapping equal spheres (rather balls) which fill a space. Space is the usual three-dimensional Euclidean space. However, ball (sphere) packing problems can be generalized to the other
3-dimensional Thurston geometries

and to higher dimensional various spaces.

In an n-dimensional space of constant curvature d_n(r) be the density of n+1 spheres of radius r mutually touching one another with respect to the simplex spanned by the centres of the spheres. L. Fejes Tó'th and H.S.M. Coxeter conjectured that in an n-dimensional space of constant curvature the density of packing spheres of radius r can not exceed d_n(r).
This conjecture has been proved by C. Roger in the Euclidean space. The 2-dimensional case has been solved by L. Fejes Tóth. In an 3-dimensional space of constant curvature the problem has been investigated by Böröoczky and Florian and it has been studied by K. Böröczky for n-dimensional space of constant curvature (n> 3).

We have studied some new aspects of the horoball and hyperball packings in n-dimensional hyperbolic space and we have realized that the ball, horoball and hyperball packing problems are not settled yet in the n-dimensional n>2 hyperbolic space.

The goal of this PhD program to generalize the above problem of finding the densest geodesic and translation ball (or sphere) packing and covering to the other 3-dimensional homogeneous geometries (Thurston geometries) .
Moreover, we will study the structure of Dirichlet-Voronoi cells related to the packing configurations.

We note here that the greatest known packing density is realized in geometry with packing density is ~0.87499429 .

We will use the unified interpretation of the Thurston geometries in the projective 3-sphere.

Required language skills: English
Number of students who can be accepted: 1

Deadline for application: 2017-05-31


2024. IV. 17.
ODT ülés
Az ODT következő ülésére 2024. június 14-én, pénteken 10.00 órakor kerül sor a Semmelweis Egyetem Szenátusi termében (Bp. Üllői út 26. I. emelet).

 
All rights reserved © 2007, Hungarian Doctoral Council. Doctoral Council registration number at commissioner for data protection: 02003/0001. Program version: 2.2358 ( 2017. X. 31. )