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Author Buhrman, Harry ♦ Franklin, Matthew ♦ Garay, Juan A. ♦ Hoepman, Jaap-Henk ♦ Tromp, John ♦ Vitnyi, Paul
Source ACM Digital Library
Content type Text
Publisher Association for Computing Machinery (ACM)
File Format PDF
Copyright Year ©1999
Language English
Subject Domain (in DDC) Computer science, information & general works ♦ Data processing & computer science
Subject Keyword Coalition forming ♦ Computational complexity ♦ Computer networks ♦ Datastructures ♦ Discrete algorithms ♦ Distributed computation ♦ Mutual search
Abstract We introduce a search problem called “mutual search” where $\textit{k}$ agents, arbitrarily distributed over $\textit{n}$ sites, are required to locate one another by posing queries of the form “Anybody at site $\textit{i}?”.$ We ask for the least number of queries that is necessary and sufficient. For the case of two agents using deterministic protocols, we obtain the following worst-case results: In an oblivious setting (where all pre-planned queries are executed), there is no savings: $\textit{n}™1$ queries are required and are sufficient. In a nonoblivious setting, we can exploit the paradigm of “no news is also news” to obtain significant savings: in the synchronous case $0.586\textit{n}$ queries are required; in the asynchronous case $0.896\textit{n}$ queries suffice and a fortiori $0.536\textit{n}$ queries are required; for o<fen lp="par">n<rp post="par"> queries and all radomized protocols require at least $0.25\textit{n}$ worst-case expected queries. The graph-theoretic framework we formulate for expressing and analyzing algorithms for this problem may be of independent interest.
ISSN 00045411
Age Range 18 to 22 years ♦ above 22 year
Educational Use Research
Education Level UG and PG
Learning Resource Type Article
Publisher Date 1999-07-01
Publisher Place New York
e-ISSN 1557735X
Journal Journal of the ACM (JACM)
Volume Number 46
Issue Number 4
Page Count 20
Starting Page 517
Ending Page 536


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Source: ACM Digital Library