English

Musical chairs

Combinatorics 2012-08-06 v1 Computer Science and Game Theory

Abstract

In the {\em Musical Chairs} game MC(n,m)MC(n,m) a team of nn players plays against an adversarial {\em scheduler}. The scheduler wins if the game proceeds indefinitely, while termination after a finite number of rounds is declared a win of the team. At each round of the game each player {\em occupies} one of the mm available {\em chairs}. Termination (and a win of the team) is declared as soon as each player occupies a unique chair. Two players that simultaneously occupy the same chair are said to be {\em in conflict}. In other words, termination (and a win for the team) is reached as soon as there are no conflicts. The only means of communication throughout the game is this: At every round of the game, the scheduler selects an arbitrary nonempty set of players who are currently in conflict, and notifies each of them separately that it must move. A player who is thus notified changes its chair according to its deterministic program. As we show, for m2n1m\ge 2n-1 chairs the team has a winning strategy. Moreover, using topological arguments we show that this bound is tight. For m2n2m\leq 2n-2 the scheduler has a strategy that is guaranteed to make the game continue indefinitely and thus win. We also have some results on additional interesting questions. For example, if m2n1m \ge 2n-1 (so that the team can win), how quickly can they achieve victory?

Keywords

Cite

@article{arxiv.1208.0813,
  title  = {Musical chairs},
  author = {Yehuda Afek and Yakov Babichenko and Uriel Feige and Eli Gafni and Nati Linial and Benny Sudakov},
  journal= {arXiv preprint arXiv:1208.0813},
  year   = {2012}
}

Comments

arXiv admin note: substantial text overlap with arXiv:1106.2065

R2 v1 2026-06-21T21:46:01.275Z