Negotiation Games (with abstract)

TL;DR

This paper introduces a game-theoretic analysis of negotiation models, focusing on coalition strategies to control negotiation termination and outcomes, with complexity results varying from EXPTIME to PTIME depending on the model's determinism.

Contribution

It initiates the study of game-theoretic problems in negotiation models and provides complexity classifications for coalition problems under different conditions.

Findings

General negotiation problems are EXPTIME-complete.

For sound and deterministic negotiations, problems are solvable in PTIME.

Input size can be exponentially smaller than the state space.

Abstract

Negotiations, a model of concurrency with multi party negotiation as primitive, have been recently introduced in arXiv:1307.2145, arXiv:1403.4958. 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.