In this paper we present CABRO, an algorithm for solving the winner determination problem related to single-unit combinatorial auctions. The algorithm is divided in three main phases. The first phase is a pre-processing step with some reduction techniques. The second phase calculates an upper and a lower bound based on a linear programming relaxation in order to delete more bids. Finally, the t...

In this thesis three different approaches to the Winner Determination Problem (WDP) for Mixed Multi-Unit Combinatorial Auctions (MMUCA) are explored. The first, due to [Cerquides et al., 2007] is based on a traditional integer programming approach. The second, due to [Uckelman and Endriss, 2007] is based on constraint programing and the third is based on a division of the original problem in tw...

A possible winner of an election is a candidate that has, in some kind of incomplete-information election, the possibility to win in a complete extension of the election. The first type of problem we study is the Possible co-Winner with respect to the Addition of New Candidates (PcWNA) problem, which asks, given an election with strict preferences over the candidates, is it possible to make a d...

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Online innovation contests have been used by more and more firms for idea seeking and problem solving. Most studies of contests take the perspective of innovation seekers, and little is known about solvers’ strategies and responses. However, contest performance also relies on understanding solver responses. This paper provides insights to these questions. Specifically, we show that past experie...

Combinatorial auctions can be used to reach efficient resource and task allocations in multiagent systems where the items are complementary or substitutable. Determining the winners is NPcomplete and inapproximable, but it was recently shown that optimal search algorithms do very well on average. This paper presents a more sophisticated search algorithm for optimal (and anytime) winner determin...

The main idea of the distance rationalizability approach to view the voters’ preferences as an imperfect approximation to some kind of consensus is deeply rooted in social choice literature. It allows one to define (“rationalize”) voting rules via a consensus class of elections and a distance: a candidate is said to be an election winner if she is ranked first in one of the nearest (with respec...

We consider online content recommendation with implicit feedback through pairwise comparisons, formalized as the so-called dueling bandit problem. We study the dueling bandit problem in the Condorcet winner setting, and consider two notions of regret: the more well-studied strong regret, which is 0 only when both arms pulled are the Condorcet winner; and the less well-studied weak regret, which...

The POSSIBLE WINNER problem asks whether some distinguished candidate may become the winner of an election when the given incomplete votes are extended into complete ones in a favorable way. POSSIBLE WINNER is NP-complete for common voting rules such as Borda, many other positional scoring rules, Bucklin, Copeland etc. We investigate how three different parameterizations influence the computati...