Title
The Kneser-Poulsen Conjecture for Special Contractions.
Abstract
The Kneser–Poulsen conjecture states that if the centers of a family of N unit balls in \({\mathbb E}^d\) are contracted, then the volume of the union (resp., intersection) does not increase (resp., decrease). We consider two types of special contractions. First, a uniform contraction is a contraction where all the pairwise distances in the first set of centers are larger than all the pairwise distances in the second set of centers. We obtain that a uniform contraction of the centers does not decrease the volume of the intersection of the balls, provided that \(N\ge (1+\sqrt{2})^d\). Our result extends to intrinsic volumes. We prove a similar result concerning the volume of the union. Second, a strong contraction is a contraction in each coordinate. We show that the conjecture holds for strong contractions. In fact, the result extends to arbitrary unconditional bodies in the place of balls.
Year
DOI
Venue
2018
10.1007/s00454-018-9976-1
Discrete & Computational Geometry
Keywords
Field
DocType
Kneser–Poulsen conjecture, Alexander’s contraction, Ball-polyhedra, Volume of intersections of balls, Volume of unions of balls, Blaschke–Santalo inequality, 52A20, 52A22
Topology,Combinatorics,Ball (bearing),Conjecture,Mathematics
Journal
Volume
Issue
ISSN
60
4
Discrete Comput. Geom. 60/4 (2018) 967-980
Citations 
PageRank 
References 
1
0.40
2
Authors
2
Name
Order
Citations
PageRank
Károly Bezdek13914.90
Marton Naszodi2217.87