4月10日(金): 16:20-18:40 富士見校舎4階404教室
16:20-17:25
発表者1: 土橋俊寛 (大東文化大学経済学)
タイトル: Level-k Analysis of Second-price Auction with Buy Price: An Experimental Study
概要: This study experimentally investigates the impact of the number of competitors and the discount factor applied to a bidder's value on buyout decisions in a second-price auction with a buyout option. Additionally, the study examines the effects of the number of competitors and the ambiguity (Knightian uncertainty) of the discount factor on buyout decisions. The major findings are as follows. First, subjects are more likely to exercise a buyout option when more participants are involved or their valuations are discounted more, as theory predicts. Second, the buyout frequency is intermediate when participants face uncertainty about the number of bidders and discount factors, inconsistent with the theoretical predicts assuming the maximin utility hypothesis. Third, there is a slight tendency toward overbidding. Among the other findings, the differences in buyout and bidding behavior associated with Cognitive Reflection Test (CRT) scores were of particular significance.
17:35-18:40
発表者2: 栗原崇 (東京理科大学経営学部)
タイトル：An axiomatic analysis of the difference between variance-to-mean ratio and alpha-Gini coefficient (joint work with Koichi Suga)
概要：This paper studies intermediate statistical inequality measurements that balance absolute and relative sensitivity. We provide an axiomatic analysis of the variance-to-mean ratio (VMR) and compare it with the α-Gini coefficient. We show that VMR satisfies a set of standard normative properties for inequality measurement. We further introduce the VMR family and prove that every member of the family satisfies the same properties. In contrast, we show that the α-Gini coefficient does not preserve inequality comparisons under income scaling, whereas VMR does. Furthermore, VMR strictly decreases under averaging of income distributions with identical inequality levels, whereas the α-Gini coefficient remains unchanged under such averaging when income rankings are preserved.
5月8日(金): 16:20-17:50 富士見校舎4階404教室
発表者: 岡田章 (一橋大学名誉教授)
タイトル: Collusive Behaviour, Efficiency and Cheap Talk Negotiation in Repeated Games (jointly with Hamid Sabourian)
概要: This paper addresses the relationship between cheap talk negotiation and collusion/efficiency in repeated games by explicitly modelling the negotiation. At each date, players bargain over how to play the continuation game and thereafter they play a stage game G. We consider equilibria that are measurable with respect to the latest agreement - as they are salient/focal features of the past. We show equilibrium payoffs are bounded below by that of a Nash equilibrium of G and are weakly renegotiation-proof. Our main results are: a non-babbling efficient equilibrium exists in many games if the discount factor d is high, and every equilibrium payoff is either babbling or efficient in the limit as d goes to 1. Finally, we check the robustness of the latter result to two perturbations: complexity costs and trustworthy/honourable players. Equilibria that survive the former perturbation are efficient or induce one-shot Nash equilibria and equilibria that survive the latter are efficient.
6月5日(金): 16:20-18:40 富士見校舎4階404教室
16:20-17:00
発表者1: David Lowing (Ecole Normale Supérieure of Rennes)
タイトル: Copyright claims and revenue allocation on streaming platforms
概要: This paper examines how to allocate the revenue generated by content creation on streaming platforms when creators may hold overlapping copyright claims over the work of others. We develop a stylized model of such environments and propose the Equal Rights allocation rule. We provide three axiomatic characterizations of this rule based on principles directly relevant to our setting. Using a cooperative game-theoretic approach, we define content creation games that capture revenue generation under copyright constraints. We show that the Equal Rights rule always produces Core-stable allocations, while maintaining properties that set it apart from the Shapley value.
17:10-17:50
発表者2: Federica Ceron (University of Saint-Etienne)
タイトル: Egalitarian Social Welfare Under Uncertainty (joint work with Vassili Vergopoulos)
概要: This paper provides new axiomatic foundations for egalitarian social welfare under income uncertainty. It develops a criterion that is sensitive both to inequality in expected income and to inequality in realized income. As is well known, such sensitivity requires relaxing both the Pareto principle and statewise dominance of social preferences. The paper does so by restricting these principles to a class of uncertain distributions satisfying a consistent-ranking condition: individuals are ranked in the same way across states and, symmetrically, states are ranked in the same way across individuals. Its main result characterizes social welfare by a one-stage Choquet integration defined over individual-state pairs. On consistent-ranking distributions, a Fubini-type property ensures that this double integral coincides with its iterated forms, thereby recovering Pareto unanimity when integration proceeds first over states and then individuals, and statewise dominance when the order is reversed.
18:00-18:40
発表者2: Stéphane Gonzalez (University of Saint-Etienne)
タイトル: The majority-approval rule in the categorization and selection process (with Raffaele Berzi)
概要: We study a collective decision problem in which a finite set of voters must select, for each of several categories, a subset of alternatives from a common agenda. Each voter expresses, for every alternative, both a categorical judgment — whether the alternative belongs to each category — and a general opinion. We introduce the Majority-Approval rule, a two-stage procedure that first retains, in each category, the alternatives endorsed by a majority of voters, and then selects among them those that maximize approval according to the general opinion. We provide an axiomatic characterization of this rule based on five properties: anonymity per candidate, two complement axioms relating an alternative's selection to the reversal of its categorical row, simple monotonicity, and positive responsiveness. The axiomatization clarifies how the rule combines majoritarian filtering at the category stage with approval-based selection at the final stage.