Addressing stability issues in mediated complex contract negotiations for constraint-based, non-monotonic utility spaces

Abstract

Negotiating contracts with multiple interdependent issues may yield non-monotonic, highly uncorrelated preference spaces for the participating agents. These scenarios are specially challenging because the complexity of the agents' utility functions makes traditional negotiation mechanisms not applicable. There is a number of recent research lines addressing complex negotiations in uncorrelated utility spaces. However, most of them focus on overcoming the problems imposed by the complexity of the scenario, without analyzing the potential consequences of the strategic behavior of the negotiating agents in the models they propose. Analyzing the dynamics of the negotiation process when agents with different strategies interact is necessary to apply these models to real, competitive environments. Specially problematic are high price of anarchy situations, which imply that individual rationality drives the agents towards strategies which yield low individual and social welfares. In scenarios involving highly uncorrelated utility spaces, "low social welfare" usually means that the negotiations fail, and therefore high price of anarchy situations should be avoided in the negotiation mechanisms. In our previous work, we proposed an auction-based negotiation model designed for negotiations about complex contracts when highly uncorrelated, constraint-based utility spaces are involved. This paper performs a strategy analysis of this model, revealing that the approach raises stability concerns, leading to situations with a high (or even infinite) price of anarchy. In addition, a set of techniques to solve this problem are proposed, and an experimental evaluation is performed to validate the adequacy of the proposed approaches to improve the strategic stability of the negotiation process. Finally, incentive-compatibility of the model is studied.

Predicting Behavior in Unstructured Bargaining with a Probability Distribution

“…For example, there is a growing literature focused on optimally managing negotiations between strategic, self-interested agents (Brafman & Tennenholtz, 1996;Chalamish & Kraus, 2012;Lopez-Carmona, Marsa-Maestre, Klein, & Ito, 2012). The primary difference between our paper and the current literature is that our bargaining game is unstructured, while the others use a structured game.…”

Computers That Negotiate on Our Behalf: Major Challenges for Self-sufficient, Self-directed, and Interdependent Negotiating Agents

“…This is especially important in domains where users can employ automated negotiation without any expertise, such as in the smart grid, which can result in the wrong evaluation of bids. Highly accurate models, on the other hand, also have their disadvantages: they can display complex nonlinearities [41,50], in which case even assessing the utility of a proposal can prove NP-hard [21].…”

A Baseline for Nonlinear Bilateral Negotiations: The full results of the agents competing in ANAC 2014

“…Therefore, the constraint-based nonlinear utility function with integer issues has been the one of the important topic in automated negotiations [28,29]. The existing work analyzes and defines some measures for the constraint-based nonlinear utility function [20], and other existing works try to improve the effectiveness of finding contracts in the bumpy nonlinear utility function [21,22,37,39].…”