We consider a generalization of the third degree price discrimination problem studied in Bergemann et al. (2015), where an intermediary between the buyer and the seller can design market segments to maximize any linear combination of consumer surplus and seller revenue. Unlike in Bergemann et al. (2015), we assume that the intermediary only has partial information about the buyer's value. We consider three different models of information, with increasing order of difficulty. In the first model, we assume that the intermediary's information allows him to construct a probability distribution of the buyer's value. Next we consider the sample complexity model, where we assume that the intermediary only sees samples from this distribution. Finally, we consider a bandit online learning model, where the intermediary can only observe past purchasing decisions of the buyer, rather than her exact value. For each of these models, we present algorithms to compute optimal or near optimal market segmentation. * Clearly, we need certain assumptions on the seller's behavior for any nontrivial result; there is not much we can do if the seller picks prices randomly all the time. Our assumptions can accommodate natural no regret learning algorithms on the seller side, including the Upper-Confidence-Bound (UCB) algorithm and the Explore-then-Commit (ETC) algorithm.
Contributions to the Sample Complexity of Mechanism DesignPioneered by Balcan et al. (2005), Elkind (2007), and Dhangwatnotai et al. (2015), and formalized by Cole and Roughgarden (2014), the sample complexity of mechanism design, in particular, the revenue maximization problem, has been a focal point in algorithmic game theory in the last few years Morgenstern and Roughgarden (2015); Balcan et al. (2016); Devanur et al. (2016); Morgenstern and Roughgarden (2016); Hartline and Taggart (2019); Cai and Daskalakis (2017); Gonczarowski and Nisan (2017); Gonczarowski and Weinberg (2018); Huang et al. (2018b); Guo et al. (2019).This paper adds to the literature of sample complexity of mechanism design in two-folds. The first one is conceptual: we formulate the first sample complexity problem from the viewpoint of an intermediary rather than the seller, and for the task of designing information dispersion rather than allocations and payments. We show impossibility results for the general case and, more importantly, identify sufficient conditions under which we derive positive algorithmic results.Conceptually new models often lead to new technical challenges. Our second contribution is an algorithmic ingredient that tackles such a new challenge. Let us start with a thought experiment: consider a more powerful intermediary who knows the true distributions; the seller, however, still acts according to some beliefs formed from the observed samples. Does the problem become trivial? Can the intermediary simply run the optimal segmentation w.r.t. the true distributions and expect near optimal outcomes?The answers turn out to be negative. Consider a segment for which there are two price...