KEIO RESEARCHERS INFORMATION SYSTEM

Papers 【 Display / hide 】

Papers 【 Display / hide 】

• Comparative statics of uncertainty attitude for rank-dependent subjective expected utility

  Nakada S., Ozaki H.

  Economics Letters 262 2026.03

  ISSN  01651765

  　View Summary

  AbstractThis paper considers two criteria for comparative statics of uncertainty attitude in a decision maker (DM), whose preference relation is represented by the rank-dependent subjective expected utility (RDSEU) (Nakada and Ozaki, 2025). We characterize the difference between the uncertainty attitudes of two DMs in terms of the shape of the distortion function.

  • Access to Document (DOI)

• The roles of subjective/objective probabilities in representation of preferences under uncertainty

  Nakada S., Ozaki H.

  Theory and Decision 99 ( 1-2 ) 151 - 171 2025.09

  ISSN  00405833

  　View Summary

  This paper scrutinizes the roles played by both subjective and objective probabilities in the representation of preferences under uncertainty. On the one hand, the subjective probability appears in the Choquet expected utility (CEU) preference in which the capacity can be decomposed into a unique probability and a unique strictly increasing distortion function. We call this preference the rank-dependent subjective expected utility (RDSEU). On the other hand, the objective probabilities appear in the domain of the preference consisting of the lottery acts (or the AA-acts). Given these two kinds of probabilities, this paper achieves two objectives. First, we axiomatize the RDSEU with the domain given by the AA-acts by invoking Dana (Scott, 1964) decomposition theorem. Second, supposing that the domains of all the relevant preferences are the AA-acts, we prove that if the preference is represented by the CEU, then it is probabilistically sophisticated (PS) if and only if it is the subjective expected utility (SEU), which implies that, within the class of the CEU preferences, the SEU is the only class of the PS preferences. This shows that if the axioms are imposed over the entire AA-acts, a fairly severe restriction must be assumed on the form of preference representation.

  • Access to Document (DOI)

Papers, etc., Registered in KOARA 【 Display / hide 】

Papers, etc., Registered in KOARA 【 Display / hide 】

• Group theory and economics (I) : a "groundwork" model and an interpretation of Lagrange's theorem

  Ozaki, Hiroyuki

  Mita journal of economics (慶應義塾経済学会)  118 ( 3 ) 329 (69) - 348 (88) 2026.02

  ISSN  00266760

• Growth and discounting : riemann-stieltjes integral

  Ozaki, Hiroyuki

  Mita journal of economics (慶應義塾経済学会)  112 ( 4 ) 491(127) - 506 (142) 2020.01

  ISSN  00266760

• Comparative statics : nonlinear simultaneous equations and implicit function theorem

  Ozaki, Hiroyuki

  Mita journal of economics (慶應義塾経済学会)  112 ( 2 ) 165(69) - 180(84) 2019.07

  ISSN  00266760

• Toward a theory of dynamic programming for recursive objective functions in continuous time models : "Les Préludes"

  Ozaki, Hiroyuki

  Mita journal of economics (慶應義塾経済学会)  110 ( 4 ) 531(171) - 540(180) 2018.01

  ISSN  00266760

• Mathematical economics 2017 at Keio : preface

  Ozaki, Hiroyuki

  Mita journal of economics (慶應義塾経済学会)  110 ( 4 ) 413(53) - 416(56) 2018.01

  ISSN  00266760

display all >>

Research Projects of Competitive Funds, etc. 【 Display / hide 】

Research Projects of Competitive Funds, etc. 【 Display / hide 】

• Theory and applications of Knightian uncertainty: making further advances

  2019.04

  -

  2022.03

  MEXT,JSPS, Grant-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (C), Principal investigator

• Asymmetric error minimization and its applications to economics

  2014.04

  -

  2017.03

  MEXT,JSPS, Grant-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (C), Principal investigator

  　View Summary

  The mathematical expectation of given random variable is know as the best approximate of it by a constant. Importantly, here, the error is measured by the mean-squared-error. Ozaki (2009) extends this conditioning scheme to a more general framework and succeeded in defining the conditioning scheme for a family of functionals that includes the expectation as a very special case. A key idea for this is to use more abstract measurement for errors rather than the mean-squared-error. In particular, he developed the conecept of an asymmetric error function that substantially extends the conecept of the mean-squared-error. This project applied an asymmetric error function to a more concrete economic situation, namely, Ellsberg's paradox, where the choice patterns of people observed were never able to be explained by means of the concept of usual probability. Ozaki showed that the paradox is resolved even under the traditional probability case if people adopt the asymmetric error functions.

Courses Taught 【 Display / hide 】

Courses Taught 【 Display / hide 】

• SEMINAR: MICROECONOMICS

  2026

• ADVANCED MICROECONOMICS

  2026

• SEMINAR: MATHEMATICAL ECONOMICS

  2026

• SEMINAR IN SPECIAL TOPICS

  2026

• TOPICS IN MICROECONOMICS

  2026

display all >>