We study the consequences of a solidarity property that specifies how a value for cooperative games should respond if some player forfeits his productivity, i.e., becomes a null player. Nullified solidarity states that in this case either all players weakly gain together or all players weakly...

We provide a new characterization of the Shapley value neither using the efficiency axiom nor the additivity axiom. In this characterization, efficiency is replaced by the gain-loss axiom (Einy and Haimanko, 2011), i.e., whenever the total worth generated does not change, a player can only gain...

We introduce a weighted version of the component efficient χ-value [Casajus, A., 2009. Outside options, component efficiency, and stability. Games and Economic Behavior 65 (1), 49–61] for TU games with a coalition structure. We provide characterizations both for a symmetric and for an...

The Shapley value probably is the most eminent single-point solution concept for TU-games. In its standard characterization, the null player property indicates the absence of solidarity among the players. First, we replace the null player property by a new axiom that guarantees null players...

We resolve a seeming conflict between a non-existence result on solutions to coalition formation in hedonic games [Barbera, S., Gerber, A., 2007. A note on the impossibility of a satisfactory concept of stability for coalition formation games. Economics Letters 95, 85-90] and the universal...

We study values for transferable utility games enriched by a communication graph. The most well-known such values are component-efficient and characterized by some link-deletion property. We study efficient extensions of such values: for a given component-efficient value, we look for a value...

The Shapley value certainly is the most eminent single-point solution concept for TU-games. In its standard characterization, the null player property indicates the absence of solidarity among the players. First, we replace the null player property by a new axiom that guarantees null players...

We provide new characterizations of the equal surplus division value and the equal division value as well as of the class of their convex mixtures. This way, the difference between the Shapley value, the equal division value, and the equal surplus division value is pinpointed to one axiom....