The Shapley value is a solution concept in cooperative game theory. It was
named in honor of Lloyd Shapley, who introduced it in 1951 and won the Nobel
Memorial Prize in Economic Sciences for it in 2012. To each cooperative game
it assigns a unique distribution (among the players) of a total surplus
generated by the coalition of all players. The Shapley value is characterized
by a collection of desirable properties. Hart (1989) provides a survey of the
subject.
The setup is as follows: a coalition of players cooperates, and obtains a
certain overall gain from that cooperation.