January 2026 Project: Topics in Computational Social Choice
This is the website for the January 2026 Master of Logic project on Computational Social Choice (COMSOC). The field of Computational Social Choice, located at the interface of Computer Science and AI with Mathematical Economics, deals with the design and analysis of fair and efficient methods for collective decision making, including democratic decision making. This project will, first, provide students with an introduction to the themes and methods of the field and, second, allow them to garner experience with conducting original research in this area. Our focus will be on topics in the theory of voting.
Useful material: We recommend chapters 1 and 2 of The Handbook of Computational Social Choice for a good introduction to the theory of voting.
Instructors: Ulle Endriss and Théo Delemazure.
Participants: Adomas, David, Dennis, Gidon, Matteo, Paul, Rowan
Schedule
The project will be divided into three parts:
- Part 1 (Jan 5 - 12): Introduction to Computational Social Choice and Voting Theory. Lectures and exercises.
- Part 2 (Jan 12 - 16): Students will select a recent paper from the field of Computational Social Choice and present it.
- Part 3 (Jan 16 - 30): Students will conduct research projects on the topic of their choice and write a short paper.
In the following table, we provide the schedule of lectures and meetings (updates possible).
| Date | Time | Topic | Instructor | Room | Resources |
|---|---|---|---|---|---|
| Jan 5 & 6 | Preparation | Exercise Sheet 1 | |||
| Jan 7 | 11:00 - 15:00 | Introduction to COMSOC and Voting Theory | Ulle Endriss | L2.07 | Slides Exercise Sheet 2 |
| Jan 7 | 15:00 - 16:00 | (Optional) COMSOC Video Seminar | |||
| Jan 8 | 11:00 - 15:00 | Strategic manipulation in voting | Ulle Endriss | L1.04 | Slides Exercise Sheet 3 |
| Jan 9 | 12:00 - 13:00 | Fairness lecture in the FACT AI course | Ulle Endriss | C0.05 | Slides |
| Jan 9 | 14:00 - 16:00 | Social choice with approval preferences | Théo Delemazure | L1.17 | Slides Exercise Sheet 4 |
| Jan 12 | 11:00 - 15:00 | Experiments in computational social choice | Théo Delemazure | L1.17 | Slides |
| Jan 15 | 11:00 - 15:00 | Student PresentationsMatteo + Dennis and Rowan | F1.15 | Matteo & Dennis' slides Rowan's slides | |
| Jan 16 | 11:00 - 15:00 | Student PresentationsAdomas + Gidon and David + Paul | L1.17 | Paul & David's slides Adomas & Gidon's slides | |
| Jan 20 | 11:00 - 13:00 | Project progress meeting | |||
| Jan 20 | 15:00 - 16:00 | (Optional) Online Social Choice and Welfare Seminar | |||
| Jan 21 | 15:00 - 16:00 | Talk by Xiaochen Yu in the COMSOC Seminar | L2.01 | ||
| Jan 22 | 11:00 - 13:00 | Project progress meeting | L1.12 | ||
| Jan 27 | 11:00 - 13:00 | Project progress meeting | L2.07 |
List of papers
Below are the paper assignments for the second week:
- David & Paul: Weak Strategyproofness in Randomized Social Choice (AAAI' 25) Felix Brandt, Patrick Lederer
- Adomas & Gidon: From Independence of Clones to Composition Consistency: A Hierarchy of Barriers to Strategic Nomination (EC' 25) Ratip Emin Berker, Sílvia Casacuberta, Isaac Robinson, Christopher Ong, Vincent Conitzer, Edith Elkind
- Matteo & Dennis: Diversity, Agreement, and Polarization in Elections (IJCAI' 24) Piotr Faliszewski, Andrzej Kaczmarczyk, Krzysztof Sornat, Stanisław Szufa, Tomasz Wąs
- Rowan: Approval compatible voting rules (Social Choice and Welfare, 2025) Zoi Terzopoulou, Jérôme Lang, William S. Zwicker
The other proposed papers were the following:
- Generative Social Choice. (EC' 24) Sara Fish, Paul Gölz, David C. Parkes, Ariel D. Procaccia, Gili Rusak, Itai Shapira, Manuel Wüthrich
- A Generalised Theory of Proportionality in Collective Decision Making (EC' 24) Tomáš Masařík, Grzegorz Pierczyński, Piotr Skowron
- Explaining Tournament Solutions with Minimal Supports (AAAI' 26) Clément Contet, Umberto Grandi, Jerôme Mengin
- Six Candidates Suffice to Win a Voter Majority. (STOC' 25) Moses Charikar, Alexandra Lassota, Prasanna Ramakrishnan, Adrian Vetta, Kangning Wang
- Compiling the Votes of a Subelectorate for Multi-winner Voting Rules (ADT' 24) Neel Karia and Jérôme Lang
- Voting Theory in the Lean Theorem Prover (LORI' 21) Wesley H. Holliday, Chase Norman and Eric Pacuit
Projects
During the second half of the month you will be working on a small original research project, preferably in a group of two. We will help you identify a suitable topic, but the original inspiration should come from you. The regular progress meetings will be an opportunity to use the entire group of participants as a sounding board for your ideas.
How do you identify a suitable topic?
One approach is to pick a real-world phenomenon regarding voting that fascinates you and then try to analyse that phenomenon using a method covered in the introductory lectures or making an appearance in one of the papers discussed in the second week.
Another approach is to take an existing paper as a starting point and to come up with an idea for how to extend it a little bit. Consult the COMSOC Community site for pointers to conferences and journals where work on COMSOC typically gets published. Note that many of the most exciting papers also get presented at the biannual COMSOC Workshop. It's best to focus on fairly recent papers, as that makes it less likely that others had the same idea before you already.
For a theoretical paper, you might try to come up with a corresponding experiment. For an experimental paper, you might want to try to derive some of those results analytically, at least for certain edge cases. For a paper written by economists for economists, you might identify an algorithmic problem overlooked by the authors. For a heavily computational paper, you might want to look into the normative justifications for studying the problems they discuss. On some rare occasions you might be able to generalise a result in a paper, but more likely you will be able to obtain more favourable results by focusing on a special case. Another good strategy for generating new research questions is to think about what happens when you (maybe just very slightly) change some of the assumptions made by the authors.
How to write a paper?
We will provide general advice on how to write a paper. Format your final report in line with the author instructions given to researchers submitting to IJCAI, one of the big conferences where a lot of work on COMSOC gets published. Write 3-5 pages (plus references), which is somewhat shorter than actual IJCAI papers. If you believe you absolutely need more than 5 pages (plus references), you must get approval from us before you submit. If your work involves code or data (very welcome but not at all required), discuss with us how to submit such supplementary material well before the submission deadline.
The deadline for submitting your final report (as well as any supplementary material, if applicable) is Friday, 30 January 2026, at 19:00.