CP-nets and Nash equilibria

TL;DR

This paper establishes a formal connection between CP-nets, which model qualitative preferences, and strategic games, enabling the use of game theory techniques to find optimal outcomes in preference reasoning.

Contribution

It introduces a qualitative extension of strategic games and proves that CP-net optimal outcomes correspond exactly to Nash equilibria in this framework.

Findings

Optimal outcomes of CP-nets are Nash equilibria of the extended strategic game.

Game theory techniques can be applied to find CP-net optimal outcomes.

Methods for CP-nets can be used to compute Nash equilibria in the related games.

Abstract

We relate here two formalisms that are used for different purposes in reasoning about multi-agent systems. One of them are strategic games that are used to capture the idea that agents interact with each other while pursuing their own interest. The other are CP-nets that were introduced to express qualitative and conditional preferences of the users and which aim at facilitating the process of preference elicitation. To relate these two formalisms we introduce a natural, qualitative, extension of the notion of a strategic game. We show then that the optimal outcomes of a CP-net are exactly the Nash equilibria of an appropriately defined strategic game in the above sense. This allows us to use the techniques of game theory to search for optimal outcomes of CP-nets and vice-versa, to use techniques developed for CP-nets to search for Nash equilibria of the considered games.