Meeting Technologies and Optimal Trading Mechanisms in Competitive Search Markets

In general, it is optimal for sellers to post an auction without a reserve price but with a fee, paid by all buyers who meet with the seller. However, the authors define a novel condition on meeting technologies, which they call invariance, and show that meeting fees are equal to zero if and only if this condition is satisfied. Finally, the authors discuss how invariance is related to other properties of meeting technologies identified in the literature.