  We present the choreography enactment pricing game, a cooperative
game-theoretic model for the study of scheduling of jobs using competitor
service providers. A choreography (a peer-to-peer service composition model)
needs a set of services to fulfill its jobs requirements. Users must choose,
for each requirement, which service providers will be used to enact the
choreography at lowest cost. Due to the lack of centralization, vendors can
form alliances to control the market. We show a novel algorithm capable of
detecting alliances among service providers, based on our study of the
bargaining set of this game.
