Strength of preference over complementary pairs axiomatizes alpha-MEU preferences
在Anscombe-Aumann框架下首次对所有α∈[0,1]\{1/2}的α-MEU模型给出公理化刻画，通过弱化不确定性厌恶和强化明显占优两个新公理，并揭示模型参数的行为含义。
Preferences over acts have an α-Maxmin Expected Utility (α-MEU) representation if they can be represented by the α-mixture of the worst and the best expected utility over a set of priors. The case α=1 is the Maxmin Expected Utility (MEU) model characterized in Gilboa and Schmeidler (1989). This paper provides the first axiomatic characterization of the α-MEU model in the Anscombe-Aumann framework for all α∈[0,1]﹨{12}. My first axiom is a weakening of Uncertainty Aversion, the second axiom is a strengthening of Obvious Dominance. Both axioms rely on the concept of complementary pairs (Siniscalchi, 2009). I show that the two parameters of the model are uniquely set identified with a one-to-one monotone relationship. The set of α-values that allow a representation have a clear behavioural interpretation and can be elicited from choice data. These results clarify the behavioural implications of the model, which is crucial for decision-theoretic interpretations, applications, and testing/falsification.