Rationalizing Choice Functions by Multiple Rationales

Gil Kalai, Ariel Rubinstein & Ran Spiegler

The paper presents a notion of rationalizing choice functions that violate the “Independence of Irrelevant Alternatives” axiom. A collection of linear orderings is said to provide a rationalization by multiple rationales for a choice function if the choice from any choice set can be rationalized by one of the orderings. We characterize a tight upper bound on the minimal number of orderings that is required to rationalize arbitrary choice functions, and calculate the minimal number for several specific choice procedures.

November, 2001
Published in: 
Econometrica 70 (2002), 2481-2488.