We provide a necessary and sufficient condition under which core allocations treat substitute players equally. The core of a game satisfies the equal treatment property if and only if no player needs the participation of all of her substitutes to attain her core payoffs. We show how this...

A family of core extensions for cooperative TU-games is introduced. These solution concepts are non-empty when applied to non-balanced games yet coincide with the core whenever the core is non-empty. The extensions suggest how an exogenous regulator can sustain a stable and efficient outcome,...

We give an axiomatization of the aspiration core on the domain of all TU-games using a relaxed feasibility condition, non-emptiness, individual rationality, and generalized versions of the reduced game property (consistency) and superadditivity. Our axioms also characterize the C-core...

We propose an axiomatic framework that allows a unified analysis of the core and three other related cooperative solution concepts that are applicable even when the core itself is empty. Existing axiomatizations of the core and similar concepts of a cooperative game include the desired form of...