Organizers

dr Oskar Skibski
dr hab. Piotr Skowron

Information

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

Research fields

List of talks

April 11, 2024, 12:15 p.m.
Piotr Kępczyński (University of Warsaw)
Extending node centrality measures to group centrality measures
During the presentation I will talk about the problem of creating group centrality measures based on node centrality measures. I will show previously known and obvious extension methods and discuss their pros and cons. I …
March 21, 2024, 12:15 p.m.
Krzysztof Apt (CWI, Amsterdam and University of Warsaw)
Characterization of Incentive Compatible Single-parameter Mechanisms Revisited
We review the characterization of incentive compatible single-parameter mechanisms introduced by Archer and Tardos in 2001. We argue that the claimed (and often cited) uniqueness result has not been established in the computer science literature …
Feb. 29, 2024, 12:15 p.m.
Sonja Kraiczy
Stability in Random Hedonic Games
Partitioning a large group of employees into teams can prove difficult because unsatisfied employees may want to transfer to other teams. In this case, the team (coalition) formation is unstable and incentivises deviation from the …
Feb. 1, 2024, noon
Tomáš Masařík (University of Warsaw)
A Generalised Theory of Proportionality in Collective Decision Making
We consider a voting model, where a number of candidates need to be selected subject to certain feasibility constraints. The model generalises committee elections (where there is a single constraint on the number of candidates …
Jan. 25, 2024, 12:15 p.m.
Piotr Faliszewski (AGK University of Science and Technology)
Guide to Experiments in COMSOC
In this talk I will discuss how numerical experiments on elections were typically performed in computational social choice and what we can learn from it. In particular, we will see what election sizes were considered …
Dec. 7, 2023, 10:15 a.m.
Tomasz Wąs (LAMSADE, Paryż)
Terrible) Chore
We study the fair allocation of mixtures of indivisible goods and chores under lexicographic preferences—a subdomain of additive preferences. A prominent fairness notion for allocating indivisible items is envy-freeness up to any item (EFX). Yet, …
Nov. 30, 2023, 12:15 p.m.
Marcin Dziubiński (University of Warsaw)
Interconnected Battles
We study a model of multibattle contest with two players and spillovers of efforts between battles. The players distribute their costly efforts across the battles. Each battle receives effort assigned to it directly (real efforts) as well as …
Nov. 23, 2023, 12:15 p.m.
Marcin Waniek (University of Warsaw)
Modelling global market access using networks
In this (very much in progress) work we use network science techniques to model access of different locations around the world to the global market. It was shown in the literature that it is possible …
Nov. 9, 2023, noon
Grzegorz Lisowski (AGH University of Science and Technology)
Strategic Cost Selection in Participatory Budgeting
We study strategic behaviour of project proposers in the context of approval-based participatory budgeting, assuming that the votes are fixed and known and the proposers want to set as high project prices as possible, provided that their …
Oct. 19, 2023, 12:15 p.m.
Georgios Papasotiropoulos (Athens University of Economics and Business)
Conditional Approval Voting: Winner Determination, Strategic Control and Proportionality Considerations
Picture a group of friends in Warsaw deciding on a shared meal: a starter and a main course. One among them loves pierogi and would like to go for bigos afterwards--easy to vote for in the classical approval voting …
Oct. 9, 2023, 10:15 a.m.
Makoto Yokoo (Kyushu University)
Matching Market Design with Constraints
Two-sided matching deals with finding a desirable combination of two parties, e.g., students and colleges, workers and companies, and medical residents to hospitals. Beautiful theoretical results on two-sided matching have been obtained, i.e., the celebrated Deferred Acceptance mechanism is …
Oct. 5, 2023, noon
Oskar Skibski (University of Warsaw)
Vitality Indices and Game-Theoretic Centralities
Vitality indices form a natural class of centrality measures that assess the importance of a node based on the impact its removal has on the network. In this talk, we will discuss the connection between …
June 22, 2023, noon
Jarosław Flis (Uniwersytet Jagielloński)
Ordynacja Proporcjonalno-Lokalna - ordynacja dla Polski?
Opracowanie to przedstawia oryginalny projekt ordynacji proporcjonalno-lokalnej (dalej „ordynacji PL”), będący odpowiedzią na postulat wprowadzenia w Polsce ordynacji mieszanej. Proponowany system jest możliwie zbliżony do obecnego, choć jednocześnie wprowadza starannie przemyślane nowe elementy. Nawiązuje zarówno …
May 18, 2023, 12:15 p.m.
Natalia Kucharczuk (University of Warsaw)
Group Vitality Indices and the Shapley Value
We will start the presentation by showing a link between Vitality Indices and Shapley Value-based induced game-theoretic centralities. It is a foundation of our current research regarding extending vitality indices into groups. We propose novel …
May 4, 2023, noon
Grzegorz Pierczyński (University of Warsaw)
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 …