Omer Lev
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Natural interviewing equilibria in matching settings Open
A common assumption in matching markets is that both sides fully know their preferences. However, when there are many participants this may be neither realistic nor feasible. Instead, agents may have some partial (perhaps stochastic) infor…
Towards a More Burkean Approach to Computational Social Choice Open
In the last few years, a lot of the activity of the computational social choice community has focused on novel mechanisms for reaching decisions by large groups of people. While this research makes meaningful scientific contributions, many…
Separate but Equal: Equality in Belief Propagation for Single Cycle Graphs Open
Belief propagation is a widely used incomplete optimization algorithm, whose main theoretical properties hold only under the assumptions that beliefs are not equal. Nevertheless, there is much evidence that equality between beliefs does oc…
Ask and You Shall be Served: Representing and Solving Multi-agent Optimization Problems with Service Requesters and Providers Open
In scenarios with numerous emergencies that arise and require the assistance of various rescue units (e.g., medical, fire, \& police forces), the rescue units would ideally be allocated quickly and distributedly while aiming to minimize ca…
PeerNomination: A novel peer selection algorithm to handle strategic and noisy assessments Open
In peer selection a group of agents must choose a subset of themselves, as winners for, e.g., peer-reviewed grants or prizes. We take a Condorcet view of this aggregation problem, assuming that there is an objective ground-truth ordering o…
Predicting voting outcomes in the presence of communities, echo chambers and multiple parties Open
When individuals interact in a social network their opinions can change, at times quite significantly, as a result of social influence. \n \nIn elections, for example, while they might initially support one candidate, what their friends sa…
Predicting Voting Outcomes in the Presence of Communities, Echo Chambers and Multiple Parties Open
A recently proposed graph-theoretic metric, the influence gap, has shown to be a reliable predictor of the effect of social influence in two-party elections, albeit only tested on regular and scale-free graphs. Here, we investigate whether…
Peer Selection with Noisy Assessments Open
In the peer selection problem a group of agents must select a subset of themselves as winners for, e.g., peer-reviewed grants or prizes. Here, we take a Condorcet view of this aggregation problem, i.e., that there is a ground-truth orderin…
The Price is (Probably) Right: Learning Market Equilibria from Samples Open
Equilibrium computation in markets usually considers settings where player valuation functions are known. We consider the setting where player valuations are unknown; using a PAC learning-theoretic framework, we analyze some classes of com…
The Price is (Probably) Right: Learning Market Equilibria from Samples Open
Equilibrium computation in markets usually considers settings where player valuation functions are known. We consider the setting where player valuations are unknown; using a PAC learning-theoretic framework, we analyze some classes of com…
One Size Does Not Fit All: A Study of Badge Behavior in Stack Overflow Open
Badges are endemic to online interaction sites, from Question and Answer (Q&A) websites to ride sharing, as systems for rewarding participants for their contributions. This paper studies how badge design affects people's contributions and …
Selecting Voting Locations for Fun and Profit Open
While manipulative attacks on elections have been well-studied, only recently has attention turned to attacks that account for geographic information, which are extremely common in the real world. The most well known in the media is gerrym…
Beyond Trees: Analysis and Convergence of Belief Propagation in Graphs with Multiple Cycles Open
Belief propagation, an algorithm for solving problems represented by graphical models, has long been known to converge to the optimal solution when the graph is a tree. When the graph representing the problem includes a single cycle, the a…
Heuristic Voting as Ordinal Dominance Strategies Open
Decision making under uncertainty is a key component of many AI settings, and in particular of voting scenarios where strategic agents are trying to reach a joint decision. The common approach to handle uncertainty is by maximizing expecte…
Primarily about Primaries Open
Much of the social choice literature examines direct voting systems, in which voters submit their ranked preferences over candidates and a voting rule picks a winner. Real-world elections and decision-making processes are often more comple…
“Reverse Gerrymandering”: Manipulation in Multi-Group Decision Making Open
District-based manipulation, or gerrymandering, is usually taken to refer to agents who are in fixed location, and an external division is imposed upon them. However, in many real-world setting, there is an external, fixed division – an or…
Socially Motivated Partial Cooperation in Multi-agent Local Search Open
Partial Cooperation is a paradigm and a corresponding model, proposed to represent multi-agent systems in which agents are willing to cooperate to achieve a global goal, as long as some minimal threshold on their personal utility is satisf…
Big City vs. the Great Outdoors: Voter Distribution and How It Affects Gerrymandering Open
Gerrymandering is the process by which parties manipulate boundaries of electoral districts in order to maximize the number of districts they can win. Demographic trends show an increasingly strong correlation between residence and party a…
View article: Strategyproof Peer Selection: Mechanisms, Analyses, and Experiments
Strategyproof Peer Selection: Mechanisms, Analyses, and Experiments Open
We study an important crowdsourcing setting where agents evaluate one another and, based on these evaluations, a subset of agents are selected. This setting is ubiquitous when peer review is used for distributing awards in a team, allocati…
Seasonal Goods and Spoiled Milk: Pricing for a Limited Shelf-Life Open
We examine the case of items with a limited shelf-life where storing an item (before consumption) may carry a cost to a buyer (or distributor). For example, eggs, milk, or Groupon coupons have a fixed expiry date, and seasonal goods can su…
View article: Convergence and Quality of Iterative Voting Under Non-Scoring Rules
Convergence and Quality of Iterative Voting Under Non-Scoring Rules Open
Iterative voting is a social choice mechanism that assumes all voters are strategic, and allows voters to change their stated preferences as the vote progresses until an equilibrium is reached (at which point no player wishes to change the…
Group Recommendations: Axioms, Impossibilities, and Random Walks Open
We introduce an axiomatic approach to group recommendations, in line of previous work on the axiomatic treatment of trust-based recommendation systems, ranking systems, and other foundational work on the axiomatic approach to internet mech…
View article: Agent Failures in All-Pay Auctions
Agent Failures in All-Pay Auctions Open
All-pay auctions, a common mechanism for various human and agent interactions, suffers, like many other mechanisms, from the possibility of players' failure to participate in the auction. We model such failures, and fully characterize equi…
View article: Convergence of Iterative Scoring Rules
Convergence of Iterative Scoring Rules Open
In multiagent systems, social choice functions can help aggregate the distinct preferences that agents have over alternatives, enabling them to settle on a single choice. Despite the basic manipulability of all reasonable voting systems, i…
An Axiomatic Approach to Routing Open
Information delivery in a network of agents is a key issue for large, complex systems that need to do so in a predictable, efficient manner. The delivery of information in such multi-agent systems is typically implemented through routing p…
View article: Strategyproof Peer Selection.
Strategyproof Peer Selection. Open
S ince the beginning of civilization, societies have been selecting small groups from within. Athenian society, for example, selected a random subset of citizens to participate in the Boule, the council of citizens which ran daily affairs …
View article: Strategyproof Peer Selection: Mechanisms, Analyses, and Experiments
Strategyproof Peer Selection: Mechanisms, Analyses, and Experiments Open
We study an important crowdsourcing setting where agents evaluate one another and, based on these evaluations, a subset of agents are selected. This setting is ubiquitous when peer review is used for distributing awards in a team, allocati…