Title
Existence and hardness of conveyor belts
Abstract
An open problem of Manuel Abellanas asks whether every set of disjoint closed unit disks in the plane can be connected by a conveyor belt, which means a tight simple closed curve that touches the boundary of each disk, possibly multiple times. We prove three main results: 1. For unit disks whose centers are both x-monotone and y-monotone, or whose centers have x-coordinates that differ by at least two units, a conveyor belt always exists and can be found efficiently. 2. It is NP-complete to determine whether disks of arbitrary radii have a conveyor belt, and it remains NP-complete when we constrain the belt to touch disks exactly once. 3. Any disjoint set of n disks of arbitrary radii can be augmented by O(n) "guide" disks so that the augmented system has a conveyor belt touching each disk exactly once, answering a conjecture of Demaine, Demaine, and Palop.
Year
DOI
Venue
2020
10.37236/9782
ELECTRONIC JOURNAL OF COMBINATORICS
DocType
Volume
Issue
Journal
27.0
4.0
ISSN
Citations 
PageRank 
1077-8926
0
0.34
References 
Authors
0
10
Name
Order
Citations
PageRank
Baird Molly100.34
Sara C. Billey2327.46
Erik D. Demaine34624388.59
Martin L. Demaine459284.37
David Eppstein54897533.94
Fekete Sándor600.34
Gordon Graham700.34
Griffin Sean800.34
Joseph S.B. Mitchell94329428.84
Swanson Joshua P.1000.34