Organizers

dr Oskar Skibski
dr hab. Piotr Skowron

Information

Thursdays, 10:15 a.m. , room: 4050

Research fields

List of talks

July 6, 2022, 4 p.m.
Stanisław Szufa (AGH University in Kraków)
Numerical Experiments in Computational Social Choice
While many papers in computational social choice are theoretical, the number of experimental works is rapidly growing. During the tutorial, we will focus on experiments related to voting and participatory budgeting. We will discuss most …
June 8, 2022, 4 p.m.
Marcin Waniek (New York University Abu Dhabi)
Social diffusion sources can escape detection
Influencing (and being influenced by) others through social networks is fundamental to all human societies. Whether this happens through the diffusion of rumors, opinions, or viruses, identifying the diffusion source (i.e., the person that initiated …
May 26, 2022, 10:15 a.m.
Dorota Celińska-Kopczyńska (Instytut Informatyki, UW)
Non-Euclidean Self-Organizing Maps
Self-Organizing Maps (SOMs, Kohonen networks) belong to neural network models of the unsupervised class. Most data analysts take it for granted to use some subregions of a flat space as their data model. However, assuming …
May 12, 2022, 10:15 a.m.
Michał Jaworski (Uniwersytet Warszawski)
Phragmen 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, …
April 28, 2022, 10:15 a.m.
Dominik Peters (Université Paris Dauphine-PSL)
Fast Preference Elicitation and Fairness in Voting
Talk 1: Many decision making systems require users to indicate their preferences via a ranking. It is common to elicit such rankings through pairwise comparison queries. By using sorting algorithms, this can be achieved by …
April 14, 2022, 10:15 a.m.
Tomasz Wąs (Instytut Informatyki, UW)
Understanding Distance Measures Among Elections
Motivated by putting empirical work based on (synthetic) election data on a more solid mathematical basis, we analyze six distances among elections, including, e.g., the challenging-to-compute but very precise swap distance and the distance used …
March 31, 2022, 10:15 a.m.
Marcin Dziubiński (Instytut Informatyki, UW)
Discrete Two Player All-Pay Auction with Complete Information
We study discrete two player all-pay auction with complete information. We provide full characterization of mixed strategy Nash equilibria and show that they constitute a subset of Nash equilibria of discrete General Lotto game. We …
March 17, 2022, 10:15 a.m.
Adrian Górecki
Proportional Public Decisions
We consider a setting where a group of individuals make a number of independent decisions. The decisions should proportionally represent the views of the voters. We formulate new criteria of proportionality and analyse two rules, …
March 3, 2022, 10:15 a.m.
Balázs Sziklai (Centre for Economic and Regional Studies & Corvinus University of Budapest)
Expert selection in recommendation networks
The Weighted Top Candidate (WTC) algorithm is an expert identification method that presents an alternative for network centralities. Its main advantage is its axiomatic characterization that shows why it is especially suitable for a number …
Jan. 27, 2022, 10:30 a.m.
Michał Godziszewski (Instytut Informatyki, UW)
Attacking Similarity-Based Sign Prediction
Adversarial social network analysis explores how social links can be altered or otherwise manipulated to obscure unwanted information collection. Thus far, however, problems of this kind have not been studied in the context of signed …
Dec. 16, 2021, 10:15 a.m.
Wiktoria Kośny (Instytut Informatyki, UW)
Comparative Theoretical Analysis of Medial Centrality Measures
We study medial centrality measures that assess the role of a node in connecting others in the network. We focus on a setting with one target node t and several source nodes. We consider four …
Dec. 2, 2021, 10:15 a.m.
Stanisław Kaźmierowski (Instytut Informatyki, UW)
Computing equilibria in conflicts with multiple battlefields and majoritarian objectives
We consider computation of Nash equilibria in conflicts with multiple battlefields and majoritarian objectives. Conflicts with multiple battlefields are zero-sum two player games with succinct representation: the number of strategies of each player is exponential …
Nov. 18, 2021, 10:15 a.m.
Jorge Salas (University of Edinburgh)
A family of centrality measures for graph data based on subgraphs
Graph structured data are stored in specialized databases called graph databases. These systems let us efficiently compute queries over the graph such as looking for paths or patterns in it. Conjunctive queries are one kind …
Nov. 4, 2021, 10:15 a.m.
Oskar Skibski (Instytut Informatyki, UW)
Closeness Centrality via the Condorcet Principle
We uncover a new relation between Closeness centrality and the Condorcet principle. We define a Condorcet winner in a graph as a node that compared to any other node is closer to more nodes. In …
Oct. 21, 2021, 10:15 a.m.
Krzysztof Apt (Centrum Wiskunde & Informatica, Amsterdam, i Instytut Informatyki, UW)
Coordination Games on Graphs
For the past five years we have been studying a natural class of coordination games. In these games the players are nodes in a (possibly directed), each with a finite set of strategies, and the …