99\% Revenue via Enhanced Competition

TL;DR

This paper demonstrates that combining simple selling mechanisms with enhanced competition can nearly achieve optimal revenue in multi-item auctions, requiring significantly fewer additional buyers than previous methods.

Contribution

It introduces a novel approach that merges simple mechanisms with enhanced competition to approximate optimal revenue efficiently.

Findings

Achieves near-optimal revenue with minimal additional buyers.

Combines simple mechanisms with enhanced competition effectively.

Reduces the number of extra buyers needed compared to prior methods.

Abstract

A sequence of recent studies show that even in the simple setting of a single seller and a single buyer with additive, independent valuations over $m$ items, the revenue-maximizing mechanism is prohibitively complex. This problem has been addressed using two main approaches: (i) Approximation: the best of two simple mechanisms (sell each item separately, or sell all the items as one bundle) gives $1/6$ of the optimal revenue [BILW14]. (ii) Enhanced competition: running the simple VCG mechanism with additional $m$ buyers extracts at least the optimal revenue in the original market [EFFTW17]. Both approaches, however, suffer from severe drawbacks: On the one hand, losing $83\%$ of the revenue is hardly acceptable in any application. On the other hand, attracting a linear number of new buyers may be prohibitive. Our main result is that by combining the two approaches one can achieve the best of both worlds. Specifically, for any constant $\epsilon$ one can obtain a $(1-\epsilon)$ fraction of the optimal revenue by running simple mechanisms --- either selling each item separately or selling all items as a single bundle --- with substantially fewer additional buyers: logarithmic, constant, or even none in some cases.