Talking Your Way into Agreement: Belief Merge by Persuasive Communication

As usually considered in Social Choice theory, the problem of preference aggregation is to find a natural and fair “merge” operation (subject to various naturalness or fairness conditions), for aggregating the agents’ preferences into a single group preference. Depending on the stringency of the required fairness conditions, one can obtain either an Impossibility theorem (e.g Arrows theorem [2]) or a classification of the possible types of reasonable merge operations [1]. In this paper we propose a more “dynamic” approach to this issue. Dynamically speaking, “merging” preference relations means finding an action or a sequence of actions (a protocol) that, when applied to any arbitrary multi-agent preference model, produces a new model in which all the agents’ preference relations are the same. When the new relations are the result of a specific merge operation, we say that we have “realized” this operation via the given (sequence of) action(s). One would like to know what types of merges are realizable by using only specific types of preference-changing actions.