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122,999
Tight Bounds on the size of 2monopolies
, 1996
"... This paper deals with the question of the influence of a monopoly of vertices, seeking to gain the majority in local neighborhoods in a graph. Say that a vertex v is r controlled by a set of vertices M if the majority of its neighbors at distance r are from M . We ask how large must M be in orde ..."
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Cited by 12 (2 self)
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be in order to rmonopolize the graph, namely, rcontrol every vertex. Tight upper and lower bounds are provided for this problem, establishing that in an nvertex graph, an rmonopoly M (for any even r 2) must be of size \Omega\Gamma n 3=5 ), and that for any r 2 there exist nvertex graphs with rmonopolies
A TraceDriven Analysis of the UNIX 4.2 BSD File System
, 1985
"... We analyzed the UNIX 4.2 BSD file system by recording userlevel activity in trace files and writing programs to analyze the traces. The tracer did not record individual read and write operations, yet still provided tight bounds on what information was accessed and when. The trace analysis shows that ..."
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Cited by 277 (5 self)
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We analyzed the UNIX 4.2 BSD file system by recording userlevel activity in trace files and writing programs to analyze the traces. The tracer did not record individual read and write operations, yet still provided tight bounds on what information was accessed and when. The trace analysis shows
Tight bounds for clock synchronization
 In Proceedings of the 28th Annual ACM Symposium on Principles of Distributed Computing (PODC). ACM
"... Abstract. We present a novel clock synchronization algorithm and prove tight upper and lower bounds on the worstcase clock skew that may occur between any two participants in any given distributed system. More importantly, the worstcase clock skew between neighboring nodes is (asymptotically) at m ..."
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Cited by 23 (6 self)
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Abstract. We present a novel clock synchronization algorithm and prove tight upper and lower bounds on the worstcase clock skew that may occur between any two participants in any given distributed system. More importantly, the worstcase clock skew between neighboring nodes is (asymptotically
A Tight Analysis of the Greedy Algorithm for Set Cover
, 1995
"... We establish significantly improved bounds on the performance of the greedy algorithm for approximating set cover. In particular, we provide the first substantial improvement of the 20 year old classical harmonic upper bound, H(m), of Johnson, Lovasz, and Chv'atal, by showing that the performan ..."
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Cited by 122 (0 self)
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that the performance ratio of the greedy algorithm is, in fact, exactly ln m \Gamma ln ln m+ \Theta(1), where m is the size of the ground set. The difference between the upper and lower bounds turns out to be less than 1:1. This provides the first tight analysis of the greedy algorithm, as well as the first upper
Tight Lower Bounds for the Size of EpsilonNets
"... According to a well known theorem of Haussler and Welzl (1987), any range space of bounded VCdimension admits an εnet of size O () ..."
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Cited by 22 (1 self)
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According to a well known theorem of Haussler and Welzl (1987), any range space of bounded VCdimension admits an εnet of size O ()
Tight lower bounds for the distinct elements problem
 In FOCS
, 2003
"... We prove strong lower bounds for the space complexity of ¢¤£¦¥¨§� ©approximating the number of distinct elements �� � in a data stream. Let � be the size of the universe from which the stream elements are drawn. We show that any onepass streaming algorithm for ¢¤£¦¥¨§� ©approximating � � must us ..."
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Cited by 59 (10 self)
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We prove strong lower bounds for the space complexity of ¢¤£¦¥¨§� ©approximating the number of distinct elements �� � in a data stream. Let � be the size of the universe from which the stream elements are drawn. We show that any onepass streaming algorithm for ¢¤£¦¥¨§� ©approximating � � must
Tight Bounds for Asynchronous Renaming
, 2011
"... This paper presents the first tight bounds on the complexity of sharedmemory renaming, a fundamental problem in distributed computing in which a set of processes need to pick distinct identifiers from a small namespace. We first prove an individual lower bound of Ω(k) process steps for deterministi ..."
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Cited by 1 (0 self)
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for deterministic renaming into any namespace of size subexponential in k, where k is the number of participants. The bound is tight: it draws an exponential separation between deterministic and randomized solutions, and implies new tight bounds for deterministic concurrent fetchandincrement counters, queues
Randomized . . . : Tight Lower Bounds
, 2007
"... We study the randomized version of a computation model (introduced in [9, 10]) that restricts random access to external memory and internal memory space. Essentially, this model can be viewed as a powerful version of a data stream model that puts no cost on sequential scans of external memory (as ot ..."
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other models for data streams) and, in addition, (like other external memory models, but unlike streaming models), admits several large external memory devices that can be read and written to in parallel. We obtain tight lower bounds for the decision problems set equality, multiset equality
Tight Bounds for DepthTwo Superconcentrators
 IN PROC. OF FOCS
, 1997
"... We show that the minimum size of a depthtwo Nsuperconcentrator is \Theta(N log² N= log log N ). Before this work, optimal bounds were known for all depths except two. For the upper bound, we build superconcentrators by putting together a small number of disperser graphs; these disperser graphs are ..."
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Cited by 24 (1 self)
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optimal lower bound of \Omega\Gamma N(log N= log log N )²) on the size of N  superconcentrators. The second method, based on the work of Hansel, gives the optimal lower bound. The method of the Kovari, S'os and Tur'an can be extended to give tight lower bounds for extractors, both in terms
Results 1  10
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122,999