Proof-theoretic Analysis of Rationality for Strategic Games with Arbitrary Strategy Sets

In the context of strategic games, we provide an axiomatic proof of the statement Common knowledge of rationality implies that the players will choose only strategies that survive the iterated elimination of strictly dominated strategies. Rationality here means playing only strategies one believes to be best responses. This involves looking at two formal languages. One is first-order, and is used to formalise optimality conditions, like avoiding strictly dominated strategies, or playing a best response. The other is a modal fixpoint language with expressions for optimality, rationality and belief. Fixpoints are used to form expressions for common belief and for iterated elimination of non-optimal strategies.Comment: 16 pages, Proc. 11th International Workshop on Computational Logic in Multi-Agent Systems (CLIMA XI). To appea

Valuing Others’ Information under Imperfect Expectations

Sometimes we believe that others receive harmful information. However, Marschak’s value of information framework always assigns non-negative value under expected utility: it starts from the decision maker’s beliefs – and one can never anticipate information’s harmfulness for oneself. The impact of decision makers’ capabilities to process information and of their expectations remains hidden behind the individual and subjective perspective Marschak’s framework assumes. By introducing a second decision maker as a point of reference, this paper introduces a way for evaluating others’ information from a cross-individual, imperfect expectations perspective for agents maximising expected utility. We define the cross-value of information that can become negative – then the information is “harmfulâ€\x9D from a cross-individual perspective – and we define (mutual) cost of limited information processing capabilities and imperfect expectations as an opportunity cost from this same point of reference. The simple relationship between these two expected utility-based concepts and Marschak’s framework is shown, and we discuss evaluating short-term reactions of stock market prices to new information as an important domain of valuing others’ information. Copyright Springer Science+Business Media, LLC 2007value of information, decision under risk, imperfect expectations, cross-value of information, harmful information, stock market prices, D80, D82, D83,

Preference for flexibility in the absence of learning: the risk attitude effect

Individual choice, Preference for flexibility, Risk attitude, D01, D81,

Are More Alternatives Better for Decision-Makers? A Note on the Role of Decision Cost

While the traditional economic wisdom believes that an individual will become better off by being given a larger opportunity set to choose from, in this paper we question this belief and build a formal theoretical model that introduces decision costs into the rational decision process. We show, under some reasonable conditions, that a larger feasible set may actually lower an individual’s level of satisfaction. This provides a solid economic underpinning for the Simon prediction. Copyright Springer 2005bounded rationality, considered subset, decision cost, D11, D83,