COWLES FOUNDATION FOR RESEARCH IN ECONOMICS
AT YALE UNIVERSITY

Box 208281
New Haven, CT 06520-8281

COWLES FOUNDATION DISCUSSION PAPER NO. 1415

Two New Proofs of Afriat's Theorem

A. Fostel, H.E. Scarf, and M.J. Todd

May 2003

We provide two new, simple proofs of Afriat's celebrated theorem stating that a finite set of price-quantity observations is consistent with utility maximization if, and only if, the observations satisfy a variation of the Strong Axiom of Revealed Preference known as the Generalized Axiom of Revealed Preference.

Keywords: Afriat's theorem, SARP, GARP

JEL Classification: D11, C60