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|a Demaine, Erik D
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|a Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science
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|a Massachusetts Institute of Technology. Computer Science and Artificial Intelligence Laboratory
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|a Demaine, Martin L
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|a Existence and hardness of conveyor belts
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|b The Electronic Journal of Combinatorics,
|c 2020-12-11T13:59:31Z.
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|z Get fulltext
|u https://hdl.handle.net/1721.1/128809
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|a 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.
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|a Article
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|t 10.37236/9782
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|t Electronic Journal of Combinatorics
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