The Power of Tokens: Rendezvous and Symmetry Detection for Two Mobile Agents in a Ring
نویسندگان
چکیده
Rendezvous with detection differs from the usual rendezvous problem in that two mobile agents not only accomplish rendezvous whenever this is possible, but can also detect the impossibility of rendezvous (e.g., due to symmetrical initial positions of the agents) in which case they are able to halt. We study the problem of rendezvous with and without detection of two anonymous mobile agents in a synchronous ring. The agents have constant memory and each of them possess one or more tokens which may be left at some nodes of the ring and noticed later. We derive sharp bounds for the case of at most two tokens per agent and also explore tradeoffs between the number of tokens available to the agents and the time needed to accomplish rendezvous with detection.
منابع مشابه
Mobile Agent Rendezvous in a Ring
In the rendezvous search problem, two mobile agents must move along the n nodes of a network so as to minimize the time required to meet or rendezvous. When the mobile agents are identical and the network is anonymous, however, the resulting symmetry can make the problem impossible to solve. Symmetry is typically broken by having the mobile agents run either a randomized algorithm or different ...
متن کاملDeterministic symmetric rendezvous with tokens in a synchronous torus
In the rendezvous problem, the goal for two mobile agents is to meet whenever this is possible. In the rendezvous with detection problem, an additional goal for the agents is to detect the impossibility of a rendezvous (e.g., due to symmetrical initial positions of the agents) and stop. We consider the rendezvous problem with and without detection for identical anonymous mobile agents (i.e., ru...
متن کاملMobile Agent Rendezvous in a Synchronous Torus
We consider the rendezvous problem for identical mobile agents (i.e., running the same deterministic algorithm) with tokens in a synchronous torus with a sense of direction and show that there is a striking computational difference between one and more tokens. More specifically, we show that 1) two agents with a constant number of unmovable tokens or with one movable token each cannot rendezvou...
متن کاملOptimal Memory Rendezvous of Anonymous Mobile Agents in a Unidirectional Ring
We study the rendezvous problem with k 2 mobile agents in a n-node ring. We present a new algorithm which solves the rendezvous problem for the non-symmetric distribution of agents on the ring. The mobile agents require the use of O(log k) bit-wise size of internal memory and one indistinguishable token each. In the periodic (but not symmetric) case our new procedure allows the agents to conclu...
متن کاملRendezvous of Mobile Agents without Agreement on Local Orientation
The exploration of a connected graph by multiple mobile agents has been previously studied under different conditions. A fundamental coordination problem in this context is the gathering of all agents at a single node, called the Rendezvous problem. To allow deterministic exploration, it is usually assumed that the edges incident to a node are locally ordered according to a fixed function calle...
متن کامل