๐ค AI Summary
This study addresses revenue maximization for online advertising platforms under a uniform pricing rule and budget constraints. Focusing on markets with divisible goods and budget-constrained buyers exhibiting linear valuations, the work proposes a pricing and allocation mechanism grounded in First-Price Pacing Equilibrium (FPPE). It establishes, for the first time, that FPPE guarantees at least one-half of the optimal revenue in the offline setting and achieves a 1/4-approximation in the online setting. Furthermore, by formulating the problem via convex optimization and extending it through an EisenbergโGale-type program, the analysis is generalized to settings with concave nonlinear valuations, demonstrating robust approximation performance across valuation structures.
๐ Abstract
Motivated by autobidding systems in online advertising, we study revenue maximization in markets with divisible goods and budget-constrained buyers with linear valuations. Our aim is to compute a single price for each good and an allocation that maximizes total revenue. We show that the First-Price Pacing Equilibrium (FPPE) guarantees at least half of the optimal revenue, even when compared to the maximal revenue of buyer-specific prices. This guarantee is particularly striking in light of our hardness result: we prove that revenue maximization under individual rationality and single-price-per-good constraints is APX-hard. We further extend our analysis in two directions: first, we introduce an online analogue of FPPE and show that it achieves a constant-factor revenue guarantee, specifically a $1/4$-approximation; second, we consider buyers with concave valuation functions, characterizing an FPPE-type outcome as the solution to an Eisenberg-Gale-style convex program and showing that the revenue approximation degrades gracefully with the degree of nonlinearity of the valuations.