  Negotiations, a model of concurrency with multi party negotiation as
primitive, have been recently introduced by J. Desel and J. Esparza. We
initiate the study of games for this model. We study coalition problems: can a
given coalition of agents force that a negotiation terminates (resp. block the
negotiation so that it goes on forever)?; can the coalition force a given
outcome of the negotiation? We show that for arbitrary negotiations the
problems are EXPTIME-complete. Then we show that for sound and deterministic or
even weakly deterministic negotiations the problems can be solved in PTIME.
Notice that the input of the problems is a negotiation, which can be
exponentially more compact than its state space.
