著者

Takashi Hayashi

出版者

The Japanese Society for Mathematical Economics

雑誌

数理経済学会誌 (ISSN:24363162)

巻号頁・発行日

vol.1, pp.23-37, 2022 (Released:2022-03-31)

参考文献数

16

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Given the direct conflict between envy-freeness and Pareto efficiency when individuals have unequal labour skills, we examine what are attainable when we choose to insist on envyfreeness.

著者

Takashi Hayashi

出版者

The Japanese Society for Mathematical Economics

雑誌

数理経済学会誌 (ISSN:24363162)

巻号頁・発行日

vol.2, pp.1-10, 2023 (Released:2023-03-31)

参考文献数

24

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This paper studies how society should be risk-averse accordingly to how individuals are risk-averse. We consider two axioms, one that if everybody prefers one risky prospect over another so should the society, the other that if everybody is more risk-averse so should the society. We show that the two axioms imply dictatorship, in the sense that the social ranking over risky prospects has to be always identical with one individual's risk preference in each equivalence class of risk preferences which yield the same profile of ordinal preferences over deterministic outcomes.

著者

Takaaki Abe

出版者

The Japanese Society for Mathematical Economics

雑誌

数理経済学会誌 (ISSN:24363162)

巻号頁・発行日

vol.1, pp.38-66, 2022 (Released:2022-03-31)

参考文献数

12

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Hart and Kurz (1983) introduced four stability concepts, called α-, β-, γ-, and δ-stability. In contrast to the intensive studies on their conceptual aspects, these notions have rarely been adopted to analyze stable coalition structures in an application because the definitions consist of multiple intermediate steps. The purpose of this paper is to solve these practical difficulties. We provide an explicit form for each of the four stability concepts and reformulate each concept without using any intermediate steps. Moreover, we offer some sufficient conditions that guarantee the existence of stable coalition structures and the inclusion relation among the four stability notions. In addition, we propose a new approach to characterize the notions of stability. An application of our results to Cournot oligopoly is also provided.

著者

Norio Takeoka Takashi Ui

出版者

The Japanese Society for Mathematical Economics

雑誌

数理経済学会誌 (ISSN:24363162)

巻号頁・発行日

vol.1, pp.67-86, 2022 (Released:2022-03-31)

参考文献数

39

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A decision problem under uncertainty is often given with a piece of objective but imprecise information about the states of the world such as in the Ellsberg urn. By incorporating such information into the smooth ambiguity model of Seo [35], we characterize a class of smooth ambiguity representations whose second-order beliefs are consistent with the objective information. As a corollary, we provide an axiomatization for the second-order expected utility, which has been studied by Nau [28], Neilson [30], Grant, Polak, and Strzalecki [16], Strzalecki [37], and Ghirardato and Pennesi [11]. In our model, attitude toward uncertainty can be disentangled from a perception about uncertainty and connected with attitude toward reduction of compound lotteries.

著者

Chiaki Hara

出版者

The Japanese Society for Mathematical Economics

雑誌

数理経済学会誌 (ISSN:24363162)

巻号頁・発行日

vol.1, pp.87-116, 2022 (Released:2022-03-31)

参考文献数

18

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In the Capital Asset Pricing Model, we consider how introducing new tradable assets into markets will affect the prices of the existing ones. We prove that introducing new tradable assets decreases the market price of risk if the elasticity of the marginal rates of substitution of the mean for standard deviation with respect to the latter is greater than one for every consumer; the market price of risk increases if the elasticity is less than one; and the market price of risk is left unchanged if the elasticity is equal to one. The proof is based on the intermediate value theorem.

著者

Masaaki Katsuragi

出版者

The Japanese Society for Mathematical Economics

雑誌

数理経済学会誌 (ISSN:24363162)

巻号頁・発行日

vol.1, pp.117-125, 2022 (Released:2022-03-31)

参考文献数

19

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Economics has been criticized for lacking reality for a long time. Lawson (1997, 2003) argues that its neglect of ontology is the underlying cause of this problem rather than just the unrealistic assumptions of the models. He espouses social ontology for economics, elaborating the nature of social being. First, I examine this claim from the viewpoint of a philosophical realism, and make it clear how critical realism theorises the reality presupposed by natural science. Second, I examine Searle’s social ontology (Searle 1995, 2009) as a representative argument for philosophical theorizing of social reality. I agree his dissection of social reality, however, his theory of the creation of social reality seems to rely on the linguistic aspect too much to make sense of the materiality of the social realm. Therefore, thirdly, I sketch out how the emergence of social reality is inseparable from the emergence of economic reality as a possible solution to the morphogenesis of social reality.

出版者

The Japanese Society for Mathematical Economics

雑誌

数理経済学会誌 (ISSN:24363162)

巻号頁・発行日

vol.1, 2022 (Released:2022-03-31)

参考文献数

3

著者

M. Ali Khan Nobusumi Sagara

出版者

The Japanese Society for Mathematical Economics

雑誌

数理経済学会誌 (ISSN:24363162)

巻号頁・発行日

vol.1, pp.1-8, 2022 (Released:2022-03-31)

参考文献数

37

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We present the equivalence between the fuzzy core and the core under minimal assumptions. Due to the exact version of the Lyapunov convexity theorem in Banach spaces, we clarify that the additional structure of commodity spaces and preferences is unnecessary whenever the measure space of agents is “saturated”. As a spin-off of the above equivalence, we obtain the coincidence of the core, the fuzzy core, and the Schmeidler’s restricted core under minimal assumptions. This coincidence of the fuzzy core and the restricted core has not been articulated anywhere.

著者

Kazuya Kamiya

出版者

The Japanese Society for Mathematical Economics

雑誌

数理経済学会誌 (ISSN:24363162)

巻号頁・発行日

vol.1, pp.9-16, 2022 (Released:2022-03-31)

参考文献数

7

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In this paper, I show that real indeterminacy of stationary monetary equilibria generically arises in a wide class of models with divisible fiat money. More precisely, if a condition, which is typically satisfied in monetary transactions, holds, then the set of monetary equilibria is generically a continuum.

著者

Yukio Takeuchi

出版者

The Japanese Society for Mathematical Economics

雑誌

数理経済学会誌 (ISSN:24363162)

巻号頁・発行日

vol.1, pp.17-22, 2022 (Released:2022-03-31)

参考文献数

7

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In the Euclidean space of all real numbers, we know that the Brouwer fixed point theorem and Poincaré–Miranda’s theorem are derived directly from the intermediate value theorem. So, Brouwer’s theorem is a partial extension of the intermediate value theorem. Then, in this note, we prove an extension of the intermediate value theorem itself in the n-dimensional Euclidean space. Maybe it should be called the intermediate point principle.