Prices, Bids, Values: One ML-Powered Combinatorial Auction to Rule Them All
Ermis Soumalias, Jakob Heiss, Jakob Weissteiner, Sven Seuken
TL;DR
The paper tackles the challenge of efficiently allocating large combinatorial bundles in ICAs by learning bidder preferences through iterative queries. It introduces MLHCA, a hybrid ML-powered auction that combines demand and value queries with a mixed-training learning algorithm, augmented by a bridge bid to preserve efficiency when transitioning between query types. The authors provide a theoretical framework showing when DQs or VQs are most effective and demonstrate empirically that MLHCA achieves up to 10x reductions in efficiency loss and up to 58% fewer queries across SATS domains, while reducing bidders' cognitive load. The work highlights practical applicability to real-world spectrum-like settings by offering strong efficiency guarantees, compatibility with standard payment rules, and mechanisms to detect misreports, marking a significant advance in practical, high-widelity ML-driven ICAs.
Abstract
We study the design of iterative combinatorial auctions (ICAs). The main challenge in this domain is that the bundle space grows exponentially in the number of items. To address this, recent work has proposed machine learning (ML)-based preference elicitation algorithms that aim to elicit only the most critical information from bidders to maximize efficiency. However, while the SOTA ML-based algorithms elicit bidders' preferences via value queries, ICAs that are used in practice elicit information via demand queries. In this paper, we introduce a novel ML algorithm that provably makes use of the full information from both value and demand queries, and we show via experiments that combining both query types results in significantly better learning performance in practice. Building on these insights, we present MLHCA, a new ML-powered auction that uses value and demand queries. MLHCA substantially outperforms the previous SOTA, reducing efficiency loss by up to a factor 10, with up to 58% fewer queries. Thus, MLHCA achieves large efficiency improvements while also reducing bidders' cognitive load, establishing a new benchmark for both practicability and efficiency.
