University of Calgary
UofC Navigation


Submitted by 21232f297a57a5a... on Tue, 07/29/2014 - 10:22am

Fejes Toth Lecture, Winter 2017: Empirical Forms of Isoperimetric Inequalities in Convex Geometry

Dr. Peter Pivovarov (University of Missouri)

Friday, April 21, 2017 -

1:00pm to 2:00pm

MS 431

The 2017 Winter Fejes Toth Lecture will be given by Dr. Peter Pivovarov from the University of Missouri.

Combinatorics and Discrete Geometry Seminar

Speaker: Professor Károly Bezdek
Mar 31 2017 -
4:00pm to 5:00pm
MS 319

The Kneser--Poulsen Conjecture states that if the centers of a family of N unit balls in Euclidean d-space is contracted, then the volume of the union (resp., intersection) does not increase (resp., decrease). We consider two types of special contractions.

Online First

Title: On non-separable families of positive homothetic convex bodies

Authors: Károly Bezdek (U of C) and Zsolt Lángi (BUT, Budapest)

Journal: Discrete and Computational Geometry  


Abstract: A finite family B of balls with respect to an arbitrary norm in ℝ^is called a non-separable family if there is no hyperplane disjoint from UB that strictly separates some elements of B from all the other elements of B. In this paper we prove that if B is a non-separable family of balls of radii r_1r_2r_(n2) with respect to an arbitrary norm in ℝ^d (d2), then Ucan be covered by a ball of radius ∑_{i=1}^{n}r_i. This was conjectured by Erdős for the Euclidean norm and was proved for that case by Goodman and Goodman (Am Math Mon 52:494–498, 1945). On the other hand, in the same paper Goodman and Goodman conjectured that their theorem extends to arbitrary non-separable finite families of positive homothetic convex bodies in ℝ^dd2. Besides giving a counterexample to their conjecture, we prove that conjecture under various additional conditions.  

Welcome to the University of Calgary's Centre for Computational & Discrete Geometry (CCDG), an academic research centre housed within the Department of Mathematics & Statistics and supported by the Canada Research Chairs Program, Canada Foundation for Innovation, Natural Sciences and Engineering Research Council of Canada, Faculty of Science and the Department of Mathematics and Statistics. 

Both give invited talks at the marquee event held at the Budapest University of Technology and Economics, in Budapest, Hungary from June 21-24, 2016. 

Members of the Centre for Computational and Discrete Geometry were heavily involved in the 2016 Summer Meeting of the Canadian Mathematical Society. 

On Wednesday, June 15, 2016, Professor Bezdek gave a colloquium talk at the Mathematics Institute of the University of Pannonia in Veszprem, Hungary.

Speaks at George Mason University and the Three-Day Workshop on Discrete and Intuitive Geometry at Auburn University. 

Volume Inequalities for Arrangements of Convex Bodies, CRC Press

Professor Károly Bezdek and his PhD student Muhammad Khan are currently co-authoring the title: 

“Volume inequalities for arrangements of convex bodies”

for the prestigious Discrete Mathematics and Its Applications series of the CRC Press. 

Volume is a fundamental concept of geometry and plays a pivotal role in all the problems and applications discussed here. The above-mentioned book not only develop the theoretical foundations of the field but also emphasize its applications in geographic information systems, medical imaging and materials science. In addition, it aims at promoting the use of volume inequalities and computer-based techniques to resolve the most important and long-standing open questions in discrete geometry. 

More details about the contents of the book will soon appear here. For now here is a poster advertising the book.