Core Equilibrium

Core equilibrium in game theory refers to a situation where no group of players can improve their outcome by unilaterally changing their strategy, considering what others are doing. In other words, each participant's decision is optimal given the choices of the rest. When the game is in core equilibrium, no subset of players can deviate together to make themselves better off, ensuring stability of the current outcomes. It's a state where everyone’s strategy is collectively sustainable, meaning no coalition has an incentive to alter their plans because they are already maximizing their benefits within the group.