Cooperative Ressource Sharing With Adamant Player

TL;DR

This paper explores resource-sharing in a coalition-formation game involving cooperative players and an adamant non-cooperative player, analyzing equilibrium utilities, coalition structures, and the price of anarchy.

Contribution

It introduces a novel model combining coalition formation with an adamant player and analyzes equilibrium outcomes and efficiency metrics.

Findings

Players tend to stay alone when number exceeds 4.

Utilitarian partition often forms the grand coalition.

PoA is smaller with an intermediate-strength adamant player.

Abstract

Cooperative game theory deals with systems where players want to cooperate to improve their payoffs. But players may choose coalitions in a non-cooperative manner, leading to a coalition-formation game. We consider such a game with several players (willing to cooperate) and an adamant player (unwilling to cooperate) involved in resource-sharing. Here, the strategy of a player is the set of players with whom it wants to form a coalition. Given a strategy profile, an appropriate partition of coalitions is formed; players in each coalition maximize their collective utilities leading to a non-cooperative resource-sharing game among the coalitions, the utilities at the resulting equilibrium are shared via Shapley-value; these shares define the utilities of players for the given strategy profile in coalition-formation game. We also consider the utilitarian solution to derive the price of anarchy (PoA). We considered a case with symmetric players and an adamant player; wherein we observed that players prefer to stay alone at Nash equilibrium when the number of players (n) is more than 4. In contrast, in the majority of the cases, the utilitarian partition is grand coalition. Interestingly the PoA is smaller with an adamant player of intermediate strength. Further, PoA grows like O(n).