Cooperative games model the allocation of profit from joint actions,
following considerations such as stability and fairness. We propose the
reliability extension of such games, where agents may fail to participate in
the game. In the reliability extension, each agent only "survives" with a
certain probability, and a coalition's value is the probability that its
surviving members would be a winning coalition in the base game. We study
prominent solution concepts in such games, showing how to approximate the
Shapley value and how to compute the core in games with few agent types.
Signaling is an important topic in the study of asymmetric information in
economic settings. In particular, the transparency of information available to
a seller in an auction setting is a question of major interest. We introduce
the study of signaling when conducting a second price auction of a
probabilistic good whose actual instantiation is known to the auctioneer but
not to the bidders. This framework can be used to model impressions selling in
display advertising. We study the problem of computing a signaling scheme that
maximizes the auctioneer's revenue in a Bayesian setting.
We introduce a general technique for obtaining approximately optimal truthful
mechanisms implementing general social welfare functions without payments. We
combine a differentially private mechanism, which induces efficiency but does
not guarantee truthfulness, with a probabilistic mechanism that is truthful yet
inefficient. The combined mechanism enjoys the best of both worlds -
truthfulness and efficiency. We demonstrate the applicability of our results
for addressing open problems in facility location and in the pricing of goods.
We consider directed graphs over a set of n agents, where an edge (i,j) is
taken to mean that agent i supports or trusts agent j. Given such a graph and
an integer k\leq n, we wish to select a subset of k agents that maximizes the
sum of indegrees, i.e., a subset of k most popular or most trusted agents. At
the same time we assume that each individual agent is only interested in being
selected, and may misreport its outgoing edges to this end.