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

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.
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

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

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
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

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.
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

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
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

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.