Time versus space trade-offs for rendezvous in trees
KOSOWSKI, Adrian
Networks, Graphs and Algorithms [GANG]
Algorithmics for computationally intensive applications over wide scale distributed platforms [CEPAGE]
Networks, Graphs and Algorithms [GANG]
Algorithmics for computationally intensive applications over wide scale distributed platforms [CEPAGE]
KOSOWSKI, Adrian
Networks, Graphs and Algorithms [GANG]
Algorithmics for computationally intensive applications over wide scale distributed platforms [CEPAGE]
< Leer menos
Networks, Graphs and Algorithms [GANG]
Algorithmics for computationally intensive applications over wide scale distributed platforms [CEPAGE]
Idioma
en
Article de revue
Este ítem está publicado en
Distributed Computing. 2014-04, vol. 27, n° 2, p. 95-109
Springer Verlag
Resumen en inglés
Two identical (anonymous) mobile agents start from arbitrary nodes of an unknown tree and have to meet at some node. Agents move in synchronous rounds: in each round an agent can either stay at the current node or move to ...Leer más >
Two identical (anonymous) mobile agents start from arbitrary nodes of an unknown tree and have to meet at some node. Agents move in synchronous rounds: in each round an agent can either stay at the current node or move to one of its neighbors. We consider deterministic algorithms for this rendezvous task. The main result of this paper is a tight trade-off between the optimal time of completing rendezvous and the size of memory of the agents. For agents with $k$ memory bits, we show that optimal rendezvous time is $\Theta(n+n^2/k)$ in $n$-node trees. More precisely, if $k \geq c\log n$, for some constant $c$, we design agents accomplishing rendezvous in arbitrary trees of size $n$ {(unknown to the agents)} in time $O(n+n^2/k)$, starting with arbitrary delay. We also show that no pair of agents can accomplish rendezvous in time $o(n+n^2/k)$, even in the class of lines of known length and even with simultaneous start. Finally, we prove that at least logarithmic memory is necessary for rendezvous, even for agents starting simultaneously in a $n$-node line.< Leer menos
Palabras clave en inglés
rendezvous
anonymous agents
time
memory space
Proyecto ANR
Calculabilité et complexité en distribué - ANR-11-BS02-0014
Orígen
Importado de HalCentros de investigación