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Download the report - Femise

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• A payoff vector (ai)i S is said to be feasible for a coalition S if and only if<br />

• A payoff vector (ai)i S is said to be individually rational if and only if<br />

This states that cooperation guarantees to each layer at lease what he/she can secure<br />

alone.<br />

• Collective rationality. For any coalition in o<strong>the</strong>r words, no<br />

utility is lost.<br />

• Pareto Optimality. This axiom means that no agent can improve her own utility<br />

without hurting somebody else,<br />

In what follows, we will rely on two major approaches, considered fair, to pin down<br />

plausible solutions which satisfy <strong>the</strong> three above conditions. First, solutions have to be<br />

fair to both partners; in which case, we will discuss <strong>the</strong> core (Gillies, 1953), as a fair<br />

solution. Second, solutions have to also exhibit fairness, in this regard, we will <strong>the</strong><br />

! "+"!<br />

and<br />

discuss applications of <strong>the</strong> Shapley value (Shapley, 1953).<br />

5. The Core<br />

The core of a cooperative game is an outcome of cooperation which provides enough<br />

incentives for <strong>the</strong> agents to remain within <strong>the</strong> grand coalition. In o<strong>the</strong>r words, <strong>the</strong> core is a<br />

setting which is able to sustain a stable cooperation. The core is a set of efficient<br />

allocations from a coalition that based on <strong>the</strong> notion of stability. To every transferable<br />

utility game, <strong>the</strong> core assigns a set such as:<br />

This condition above states that no coalition S could better on its own by deviating from<br />

<strong>the</strong> grand coalition N. In o<strong>the</strong>r words, <strong>the</strong> core solution is stable when all players in <strong>the</strong><br />

grand coalition gain imputations greater than <strong>the</strong>ir stand alone payoffs, v(S).

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