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Afriat’s Theorem and Samuelson’s ‘Eternal Darkness’

Polisson, Matthew and Renou, Ludovic (2016) 'Afriat’s Theorem and Samuelson’s ‘Eternal Darkness’.' Journal of Mathematical Economics, 65. pp. 36-40. ISSN 0304-4068

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Suppose that we have access to a finite set of expenditure data drawn from an individual consumer, i.e., how much of each good has been purchased and at what prices. Afriat (1967) was the first to establish necessary and sufficient conditions on such a data set for rationalizability by utility maximization. In this note, we provide a new and simple proof of Afriat’s Theorem, the explicit steps of which help to more deeply understand the driving force behind one of the more curious features of the result itself, namely that a concave rationalization is without loss of generality in a classical finite data setting. Our proof stresses the importance of the non-uniqueness of a utility representation along with the finiteness of the data set in ensuring the existence of a concave utility function that rationalizes the data.

Item Type: Article
Uncontrolled Keywords: Afriat’s Theorem; Concavity; Revealed preference; Utility maximization
Subjects: H Social Sciences > HB Economic Theory
Divisions: Faculty of Social Sciences > Economics, Department of
SWORD Depositor: Elements
Depositing User: Elements
Date Deposited: 27 May 2016 14:14
Last Modified: 08 Jan 2022 00:33

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