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Label-guided graph exploration by a finite automaton

Published: 22 August 2008 Publication History

Abstract

A finite automaton, simply referred to as a robot, has to explore a graph, that is, visit all the nodes of the graph. The robot has no a priori knowledge of the topology of the graph, nor of its size. It is known that for any k-state robot, there exists a graph of maximum degree 3 that the robot cannot explore. This article considers the effects of allowing the system designer to add short labels to the graph nodes in a preprocessing stage, for helping the exploration by the robot. We describe an exploration algorithm that, given appropriate 2-bit labels (in fact, only 3-valued labels), allows a robot to explore all graphs. Furthermore, we describe a suitable labeling algorithm for generating the required labels in linear time. We also show how to modify our labeling scheme so that a robot can explore all graphs of bounded degree, given appropriate 1-bit labels. In other words, although there is no robot able to explore all graphs of maximum degree 3, there is a robot R, and a way to color in black or white the nodes of any bounded-degree graph G, so that R can explore the colored graph G. Finally, we give impossibility results regarding graph exploration by a robot with no internal memory (i.e., a single-state automaton).

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Published In

cover image ACM Transactions on Algorithms
ACM Transactions on Algorithms  Volume 4, Issue 4
August 2008
264 pages
ISSN:1549-6325
EISSN:1549-6333
DOI:10.1145/1383369
Issue’s Table of Contents
Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. Copyrights for components of this work owned by others than ACM must be honored. Abstracting with credit is permitted. To copy otherwise, or republish, to post on servers or to redistribute to lists, requires prior specific permission and/or a fee. Request permissions from [email protected]

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Association for Computing Machinery

New York, NY, United States

Publication History

Published: 22 August 2008
Accepted: 01 November 2007
Revised: 01 November 2007
Received: 01 August 2006
Published in TALG Volume 4, Issue 4

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Author Tags

  1. Distributed algorithms
  2. graph exploration
  3. labeling schemes

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Cited By

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  • (2024)Dispersion, Capacitated Nodes, and the Power of a Trusted ShepherdProceedings of the 25th International Conference on Distributed Computing and Networking10.1145/3631461.3632310(400-405)Online publication date: 4-Jan-2024
  • (2024)Maximal Independent Set via Mobile AgentsProceedings of the 25th International Conference on Distributed Computing and Networking10.1145/3631461.3631543(74-83)Online publication date: 4-Jan-2024
  • (2024)Optimal Dispersion in Triangular Grids: Achieving Efficiency Without Prior KnowledgeDistributed Computing and Intelligent Technology10.1007/978-3-031-81404-4_7(75-91)Online publication date: 31-Dec-2024
  • (2023)Fast Deterministic Gathering with Detection on Arbitrary Graphs: The Power of Many Robots2023 IEEE International Parallel and Distributed Processing Symposium (IPDPS)10.1109/IPDPS54959.2023.00015(47-57)Online publication date: May-2023
  • (2023)Lower and upper bounds for deterministic convergecast with labeling schemesTheoretical Computer Science10.1016/j.tcs.2023.113775952(113775)Online publication date: Mar-2023
  • (2023)Memory optimal dispersion by anonymous mobile robotsDiscrete Applied Mathematics10.1016/j.dam.2023.07.005340:C(171-182)Online publication date: 15-Dec-2023
  • (2023)Dispersion of Mobile Robots in Spite of FaultsStabilization, Safety, and Security of Distributed Systems10.1007/978-3-031-44274-2_31(414-429)Online publication date: 30-Sep-2023
  • (2023)Zero-Memory Graph Exploration with Unknown InportsStructural Information and Communication Complexity10.1007/978-3-031-32733-9_11(246-261)Online publication date: 25-May-2023
  • (2023)Fault-Tolerant Dispersion of Mobile RobotsAlgorithms and Discrete Applied Mathematics10.1007/978-3-031-25211-2_3(28-40)Online publication date: 26-Jan-2023
  • (2022)Dispersion of mobile robots using global communicationJournal of Parallel and Distributed Computing10.1016/j.jpdc.2021.11.007161:C(100-117)Online publication date: 1-Mar-2022
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