Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Targeting and Signaling in Ad Auctions   Modern ad auctions allow advertisers to target more specific segments of the
user population. Unfortunately, this is not always in the best interest of the
ad platform. In this paper, we examine the following basic question in the
context of second-price ad auctions: how should an ad platform optimally reveal
information about the ad opportunity to the advertisers in order to maximize
revenue? We consider a model in which bidders' valuations depend on a random
state of the ad opportunity. Different from previous work, we focus on a more
practical, and challenging, situation where the space of possible realizations
of ad opportunities is extremely large. We thus focus on developing algorithms
whose running time is independent of the number of ad opportunity realizations.
  We examine the auctioneer's algorithmic question of designing the optimal
signaling scheme. When the auctioneer is restricted to send a public signal to
all bidders, we focus on a well-motivated Bayesian valuation setting in which
the auctioneer and bidders both have private information, and present two main
results: 1. we exhibit a characterization result regarding approximately
optimal schemes and prove that any constant-approximate public signaling scheme
must use exponentially many signals; 2. we present a "simple" public signaling
scheme that serves as a constant approximation under mild assumptions. We then
initiate an exploration on the power of being able to send different signals
privately to different bidders. Here we examine a basic setting where the
auctioneer knows bidders' valuations, and exhibit a polynomial-time private
scheme that extracts almost full surplus even in the worst Bayes Nash
equilibrium. This illustrates the surprising power of private signaling schemes
in extracting revenue.

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The categories of this paper are: atom-ph
31
The categories of this paper are: ao-sci
12
The categories of this paper are: nucl-th
3
The categories of this paper are: physics
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The categories of this paper are: q-fin
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The categories of this paper are: math-ph
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The categories of this paper are: funct-an
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The categories of this paper are: chem-ph
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The categories of this paper are: solv-int
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The categories of this paper are: supr-con
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The categories of this paper are: bayes-an
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The categories of this paper are: econ
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The categories of this paper are: nucl-ex
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The categories of this paper are: plasm-ph
13
The categories of this paper are: quant-ph
9
The categories of this paper are: nlin