Seminar Games, Mechanisms, and Social Networks

Organizers

• dr hab. Oskar Skibski
• dr hab. Piotr Skowron, prof. ucz.

Information

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Research fields

• Algorithmic economics
• Artificial Intelligence and Multiagent Systems

List of talks

• March 18, 2021, 10:15 a.m.
  Grzegorz Pierczyński (Instytut Informatyki, UW)
  Market-Based Explanations of Collective Decisions
  We consider approval-based committee elections, in which a size-k subset of available candidates must be selected given approval sets for each voter, indicating the candidates approved by the voter. A number of axioms capturing ideas …

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• March 4, 2021, 10:15 a.m.
  Dorota Celińska-Kopczyńska (Instytut Informatyki, UW)
  Discrete Hyperbolic Random Graph Model
  The hyperbolic random graph model (HRG) has proven useful in the analysis of scale-free networks, which are ubiquitous in many fields, from social network analysis to biology. However, working with this model is algorithmically and …

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• Jan. 28, 2021, 10:15 a.m.
  Oskar Skibski (Instytut Informatyki, UW)
  Signed Graph Games: Coalitional Games with Friends, Enemies and Allies
  We extend the well-known model of graph-restricted games due to Myerson to signed graphs, where the link between any two players may be either positive or negative. Hence, in our model, it is possible to …

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• Dec. 17, 2020, 10:15 a.m.
  Michał Godziszewski (Instytut Informatyki, UW)
  An Analysis of Approval-Based Committee Rules for 2D-Euclidean Elections
  We study approval-based committee elections for the case where the voters' preferences come from a 2D-Euclidean model. We consider two main issues: First, we ask for the complexity of computing election results. Second, we evaluate …

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• Dec. 3, 2020, 10:15 a.m.
  Michał Lewandowski i Paweł Kalczyński (Zakład Analizy i Wspomagania Decyzji, SGH, College of Business and Economics, California State University – Fullerton)
  Carpooling games
  We define a new carpooling game (or more generally a task completion game) as an extension of the cost-sharing game and propose optimization algorithms to find stable allocations, i.e. match players to carpools and determine …

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• Nov. 19, 2020, 10:15 a.m.
  Michał Jaworski (Instytut Informatyki, UW)
  Phragmén Rules for Degressive and Regressive Proportionality
  We study two concepts of proportionality in the model of approval-based committee elections. In degressive proportionality small minorities of voters are favored in comparison with the standard linear proportionality. Regressive proportionality, on the other hand, …

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• Nov. 12, 2020, 10:15 a.m.
  Tomasz Wąs (Instytut Informatyki UW)
  PageRank vs. Random Walk Decay Centrality
  PageRank is one of the most important measures of node importance. However, multiple methods of manipulating PageRank have been identified. Recently, Random Walk Decay centrality was introduced as a harder to manipulate alternative to PageRank. …

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• Oct. 22, 2020, 10:15 a.m.
  Grzegorz Pierczyński (Intytut Informatyki, UW)
  Proportional Participatory Budgeting with Cardinal Utilities
  We study voting rules for participatory budgeting, where a group of voters collectively decides which projects should be funded using a common budget. We allow the projects to have arbitrary costs, and the voters to …

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• Oct. 8, 2020, 10:15 a.m.
  Marcin Dziubiński (Instytut Informatyki, UW)
  Peer selection with external referees
  The problem of peer selection is a problem facing a social planner who aims to choose a project of the highest quality from the set of projects submitted by a number of strategic agents. To …

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• March 5, 2020, 10:15 a.m.
  Michał Godziszewski (Instytut Informatyki, UW)
  Complexity of some multi-winner election rules over two-dimensional Euclidean single-peaked preferences
  For a given election E=(V,C) the preferences \{\leq_i\}_{i \in V} of voters are single-peaked when, intuitively speaking, a single issue dominates their formation. This single dominating issue is normally represented by a one-dimensional real axis …

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• Jan. 30, 2020, 10:15 a.m.
  Piotr Skowron (Instytut Informatyki, UW)
  Proportionality and the Limits of Welfarism: Fairness with respect to power
  We study two influential voting rules proposed in the 1890s by Phragmen and Thiele, which elect a committee or parliament of k candidates which proportionally represents the voters. Voters provide their preferences by approving an …

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• Jan. 23, 2020, 10:15 a.m.
  Piotr Skowron (Instytut Informatyki, UW)
  Proportionality and the Limits of Welfarism
  We study two influential voting rules proposed in the 1890s by Phragmen and Thiele, which elect a committee or parliament of k candidates which proportionally represents the voters. Voters provide their preferences by approving an …

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• Jan. 9, 2020, 10:15 a.m.
  Gleb Polevoy (Instytut Informatyki, UW)
  Hiders' Game
  A number of recent models in the literature studied various versions of the adversarial social network analysis problem. Generally speaking, this problem involves some members of a network---e.g. leaders of a covert network, political activists, …

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• Dec. 19, 2019, 10:15 a.m.
  Dorota Celińska-Kopczyńska (Instytut Informatyki, UW)
  Hyperbolic pseudo-betweenness -- initial proposition
  Centrality measures identify nodes that play an important role within the network. Betweenness centrality is interpreted roughly as the fraction of all shortest paths in the network between two nodes that contain the given node. …

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• Oct. 17, 2019, 10:15 a.m.
  Oskar Skibski (Instytut Informatyki, UW)
  Complexity of Computing the Shapley Value in Games with Externalities
  We study the complexity of computing the Shapley value in games with externalities. We focus on two representations based on marginal contribution nets (embedded MC-nets and weighted MC-nets). We show that every embedded/weighted MC-nets rule …

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