Revealed preference and indifferent selection∗

It is shown that preferences can be constructed from observed choice be-havior in a way that is robust to indifferent selection (i.e., the agent is indiffer-ent between two alternatives but, nevertheless, is only observed selecting one of them). More precisely, a suggestion by Savage (1954) to reveal indifferent selection by considering small monetary perturbations of alternatives is for-malized and generalized to a purely topological framework: preferences over an arbitrary topological space can be uniquely derived from observed behav-ior under the assumptions that they are continuous and nonsatiated and that a strictly preferred alternative is always chosen, and indifferent selection is then characterized by discontinuity in choice behavior. Two particular cases are then analyzed: monotonic preferences over a partially ordered set, and preferences representable by a continuous pseudo-utility function