Synchronous rendezvous for location-aware agents

Andrew Collins, Jurek Czyzowicz, Leszek Ga̧sieniec, Adrian Kosowski, Russell Martin

Research output: Chapter in Book/Report/Conference proceedingConference contribution

22 Scopus citations


We study rendezvous of two anonymous agents, where each agent knows its own initial position in the environment. Their task is to meet each other as quickly as possible. The time of the rendezvous is measured by the number of synchronous rounds that agents need to use in the worst case in order to meet. In each round, an agent may make a simple move or it may stay motionless. We consider two types of environments, finite or infinite graphs and Euclidean spaces. A simple move traverses a single edge (in a graph) or at most a unit distance (in Euclidean space). The rendezvous consists in visiting by both agents the same point of the environment simultaneously (in the same round). In this paper, we propose several asymptotically optimal rendezvous algorithms. In particular, we show that in the line and trees as well as in multi-dimensional Euclidean spaces and grids the agents can rendezvous in time O(d), where d is the distance between the initial positions of the agents. The problem of location-aware rendezvous was studied before in the asynchronous model for Euclidean spaces and multi-dimensional grids, where the emphasis was on the length of the adopted rendezvous trajectory. We point out that, contrary to the asynchronous case, where the cost of rendezvous is dominated by the size of potentially large neighborhoods, the agents are able to meet in all graphs of at most n nodes in time almost linear in d, namely, O(dlog2n). We also determine an infinite family of graphs in which synchronized rendezvous takes time Ω(d).

Original languageEnglish (US)
Title of host publicationDistributed Computing - 25th International Symposium, DISC 2011, Proceedings
Number of pages13
StatePublished - 2011
Externally publishedYes
Event25th International Symposium on Distributed Computing, DISC 2011 - Rome, Italy
Duration: Sep 20 2011Sep 22 2011

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Volume6950 LNCS
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349


Conference25th International Symposium on Distributed Computing, DISC 2011

ASJC Scopus subject areas

  • Theoretical Computer Science
  • Computer Science(all)


Dive into the research topics of 'Synchronous rendezvous for location-aware agents'. Together they form a unique fingerprint.

Cite this