Recommender Systems meet Mechanism Design
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Machine learning has developed a variety of tools for learning and representing high-dimensional distributions with structure. Recent years have also seen big advances in designing multi-item mechanisms. Akin to overfitting, however, these mechanisms can be extremely sensitive to the Bayesian prior that they target, which becomes problematic when that prior is only approximately known. We consider a multi-item mechanism design problem where the bidders' value distributions can be approximated by a topic model. Our solution builds on a recent robustification framework by Brustle et al., which disentangles the statistical challenge of estimating a multi-dimensional prior from the task of designing a good mechanism for it, robustifying the performance of the latter against the estimation error of the former. We provide an extension of the framework that allows us to exploit the expressive power of topic models to reduce the effective dimensionality of the mechanism design problem.
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