Solidarity Value for Network Games

Abstract

The solidarity value is an allocation rule for cooperative games that redistributes payoffs by averaging marginal contributions, promoting mutual support among coalition members. In this paper, we extend the solidarity principle to introduce an allocation rule for network games, where feasible coalitions are constrained by a communication graph. The key idea is that, within any connected coalition, a player whose marginal contribution exceeds the average marginal contribution of that coalition offers a portion of their surplus to support weaker members whose marginal contribution fall below the average. This redistribution reflects a solidarity-based adjustment within the graph-connected coalitions. We provide an axiomatic characterization of the solidarity value for networks games along the lines of Myerson value.