A Universally Efficient Dynamic Auction
for All Unimodular Demand Types
We propose a novel strategy-proof dynamic auction for efficiently allocating heterogeneous indivisible commodities. The auction applies to all unimodular demand types of Baldwin and Klemperer’s necessary and sufficient condition for competitive equilibrium which accommodate a variety of complements, substitutes, gross substitutes and complements, and any other kinds. Although bidders are not assumed to be price-takers so they can act strategically, this auction induces bidders to bid truthfully, yielding efficient outcomes. Sincere bidding is shown to be an ex post perfect equilibrium of the auction. The trading rules are simple, detail-free, privacy-preserving, error-tolerant, and independent of any probability distribution assumption.