Rate of Arbitrage and Reconciled Beliefs

Any group of risk neutral agents who hold differing beliefs is vulnerable to money pumps (arbitrage). Thus, the agents may wish to reconcile their beliefs into a new joint belief. We propose a criterion for the choice of reconciled belief based on the notion of ``rate of arbitrage.''' It is shown that there exists a unique belief (probability distribution) that minimizes the maximal expected rate of arbitrage, and an explicit formula for this belief is given.

Group deliberation and the transformation ofjudgments: an impossibility result

While a large social-choice-theoretic literature discusses the aggregation ofindividual judgments into collective ones, there is relatively little formalwork on the transformation of individual judgments in group deliberation. Idevelop a model of judgment transformation and prove a baselineimpossibility result: Any judgment transformation function satisfying someinitially plausible condition is the identity function, under which no opinionchange occurs. I identify escape routes from this impossibility result andargue that successful group deliberation must be 'holistic': individualscannot generally revise their judgments on a proposition based on judgmentson that proposition alone but must take other propositions into account too. Idiscuss the significance of these findings for democratic theory.group deliberation, judgment aggregation, judgmenttransformation, belief revision

Possibilistic Boolean games: strategic reasoning under incomplete information

Boolean games offer a compact alternative to normal-form games, by encoding the goal of each agent as a propositional formula. In this paper, we show how this framework can be naturally extended to model situations in which agents are uncertain about other agents' goals. We first use uncertainty measures from possibility theory to semantically define (solution concepts to) Boolean games with incomplete information. Then we present a syntactic characterization of these semantics, which can readily be implemented, and we characterize the computational complexity

Looking at Mean-Payoff through Foggy Windows

Mean-payoff games (MPGs) are infinite duration two-player zero-sum games played on weighted graphs. Under the hypothesis of perfect information, they admit memoryless optimal strategies for both players and can be solved in NP-intersect-coNP. MPGs are suitable quantitative models for open reactive systems. However, in this context the assumption of perfect information is not always realistic. For the partial-observation case, the problem that asks if the first player has an observation-based winning strategy that enforces a given threshold on the mean-payoff, is undecidable. In this paper, we study the window mean-payoff objectives that were introduced recently as an alternative to the classical mean-payoff objectives. We show that, in sharp contrast to the classical mean-payoff objectives, some of the window mean-payoff objectives are decidable in games with partial-observation

07351 Abstracts Collection -- Formal Models of Belief Change in Rational Agents

From 26.08. to 30.08.2007, the Dagstuhl Seminar 07351 ``Formal Models of Belief Change in Rational Agents\u27\u27 was held in the International Conference and Research Center (IBFI), Schloss Dagstuhl. During the seminar, several participants presented their current research, and ongoing work and open problems were discussed. Abstracts of the presentations given during the seminar as well as abstracts of seminar results and ideas are put together in this paper. The first section describes the seminar topics and goals in general. Links to extended abstracts or full papers are provided, if available

Merging Automobile Insurance Regulatory Bodies: The Case of Atlantic Canada

The recent automobile liability insurance crisis in Atlantic Canada has prompted the four provincial legislations (Newfoundland and Labrador, New Brunswick, Nova Scotia and Prince Edward Island) to setup a task force to redesign, if necessary, the personal automobile insurance system. After reviewing some of the most interesting new regulatory changes, our paper proposes a new area of discussion: The merger of the four provincial insurance regulatory bodies to combat insurance fraud. We base our paper on the principle that recent premium increases are mainly due to an increase in insurance fraud. We show that merging the regulatory bodies may reduce insurance fraud if the merger allows savings on the average audit cost and on the development of better fraud detection technology. Finally, we suggest a fraud reducing insurance taxation scheme to finance insurance fraud investigations. La récente crise dans le Canada Atlantique au sujet de l'assurance de la responsabilité civile des automobilistes a contraint les gouvernements des quatre provinces (Terre-Neuve et Labrador, Nouveau-Brunswick, Nouvelle-Écosse et l'Île-du-Prince-Édouard) à mettre en place une commission pour étudier la possibilité de réorganiser, si nécessaire, leur système d'assurance automobile. Après avoir analysé les plus intéressantes modifications à la réglementation mises en place dans ces provinces, notre étude offre un nouveau terrain de discussion, soit la fusion des quatre réglementations provinciales afin de combattre la fraude à l'assurance. Notre étude se base sur le principe que les récentes augmentations dans les primes sont attribuables à une augmentation de la fraude à l'assurance dans ces provinces. En fusionnant les réglementations des quatre provinces, nous montrons que la fraude à l'assurance peut diminuer si la fusion permet d'épargner une partie du coût de vérification encouru par les assureurs lors de réclamations douteuses. Également, nous montrons qu'une telle fusion peut permettre de développer une meilleure technologie de vérification des réclamations. Nous terminons le papier en suggérant un système de taxation particulier qui non seulement peut financer les investissements nécessaires pour combattre la fraude, mais peut également réduire la fraude directement.insurance fraud, asymmetric information, insurance taxation, public policy, fraude à l'assurance, information asymétrique, taxation à l'assurance, politique publique

Merging automobile regulatory bodies: The case of Atlantic Canada

The recent automobile liability insurance crisis in Atlantic Canada has prompted the four provincial legislations (Newfoundland and Labrador, New Brunswick, Nova Scotia and Prince Edward Island) to setup a task force to redesign, if necessary, the personal automobile insurance system. After reviewing some of the most interesting new regulatory changes, our paper proposes a new area of discussion: The merger of the four provincial insurance regulatory bodies to combat insurance fraud. We base our paper on the principle that recent premium increases are mainly due to an increase in insurance fraud. We show that merging the regulatory bodies may reduce insurance fraud if the merger allows savings on the average audit cost and on the development of better fraud detection technology. Finally, we suggest a fraud reducing insurance taxation scheme to finance insurance fraud investigations. --Insurance Fraud,Asymmetric Information,Insurance Taxation,Public Policy