An Approach to Scalable Multi-issue Negotiation: Decomposing the Contract Space Based on Issue Interdependencies

Most real-world negotiation involves multiple interdependent issues, which makes an agent´s utility functions nonlinear. Traditional negotiation mechanisms, which were designed for linear utilities, do not fare well in nonlinear contexts. One of the main challenges in developing effective nonlinear negotiation protocols is scalability; they can produce excessively high failure rates, when there are many issues, due to computational intractability. One reasonable approach to reducing computational cost, while maintaining good quality outcomes, is to decompose the utility space into several largely independent sub-spaces. In this paper, we propose a method for decomposing a utility space based on four types of issue inter-dependencies. This method allows good outcomes with greater scalability than previous efforts. We also analyze how the types of issue interdependency influence the solution optimality and failure rate.