Patrick Lederer

Postdoctoral Fellow at UNSW Sydney

Email: p.lederer@unsw.edu.au
Address: UNSW, Building K17, Room 307, Sydney NSW 2052, Australia

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Short Bio

I am a postdoctoral researcher in the Algorithmic Decision Theory group of Prof. Haris Aziz at UNSW Sydney since April 2024. Before coming to Australia, I obtained a PhD in computer science at the Technical University of Munich, where I was a member of the group led by Prof. Felix Brandt. My research focuses on (computational) social choice, in particular on how to design normatively appealing voting rules or mechanisms for assignment, matching, or fair division. Moreover, I enjoy using computer-aided theorem proving to find new results in these domains.

Publications

Working Papers
  1. P. Lederer. Strategyproof randomized social choice for restricted sets of utility functions.2025. Working paper. [ pdf ]
  2. H. Aziz, P. Lederer, D. Peters, J. Peters, A. Ritossa. Committee monotonicity and proportional representation for ranked preferences. 2025. Working paper. [ pdf ]
  3. P. Lederer. Robust voting rules on the interval domain. 2024. Working paper. [ pdf ]
  4. H. Aziz, P. Lederer, X. Lu, M. Suzuki, and J. Vollen. Sequential payment rules: Approximately fair budget divisions via simple spending dynamics. 2024. Working paper. [ pdf ]
  5. E. Elkind, M. Greger, P. Lederer, W. Suksompong, and N. Teh. Settling the score: Portioning with cardinal preferences. 2024. Working paper. [ pdf ]
Journal Publications
  1. P. Lederer. Bivariate scoring rules: Unifying the characterizations of positional scoring rules and Kemeny's rule. Journal of Economic Theory, 218:105836, 2024. [ link | pdf ]
  2. F. Brandt, P. Lederer, and R. Romen. Relaxed notions of Condorcet-consistency and efficiency for strategyproof social decision schemes. Social Choice and Welfare, 63:19–55, 2024. [ link | pdf ]
  3. F. Brandt, P. Lederer, and W. Suksompong. Incentives in social decision schemes with pairwise comparison preferences. Games and Economic Behavior, 142:266-291, 2023. [ link | pdf ]
  4. F. Brandt and P. Lederer. Characterizing the top cycle via strategyproofness. Theoretical Economics, 18(2):837-883, 2023. [ link | pdf]
  5. F. Brandt, M. Bullinger, and P. Lederer. On the indecisiveness of Kelly-strategyproof social choice functions. Journal of Artificial Intelligence Research, 73:1093-1130, 2022. [ link | pdf ]
Conference Publications
  1. H. Aziz, H. Chan, P. Lederer, S. Narang, T. Walsh. Distance preservation games. In Proceedings of the 34th International Joint Conference on Artificial Intelligence (IJCAI), 2025. Forthcoming. [ pdf]
  2. F. Frank and P. Lederer. The metric distortion of randomized social choice functions: C1 maximal lottery rules and simulations. In Proceedings of the 24th International Conference on Autonomous Agents and Multiagent Systems (AAMAS), 2025. Forthcoming. [ pdf ]
  3. F. Brandt and P. Lederer. Weak strategyproofness in randomized social choice. In Proceedings of the 39th AAAI Conference on Artificial Intelligence (AAAI), 2025, pages 13667-13674. [ link | pdf ]
  4. P. Lederer, D. Peters, and T. Wąs. The squared Kemeny rule for averaging rankings. In Proceedings of the 25th ACM Conference on Economics and Computation, page 755. 2024. [ link | pdf ]
  5. M. Bullinger, C. Dong, P. Lederer, and C. Mehler. Participation incentives in approval-based committee elections. In Proceedings of the 38th AAAI Conference on Artificial Intelligence (AAAI), pages 9546-9554. 2024. [ link | pdf ]
  6. C. Dong and P. Lederer. Refined characterizations of approval-based committee scoring rules. In Proceedings of the 38th AAAI Conference on Artificial Intelligence (AAAI), 2024, pages 9670-9678. [ link | pdf ]
  7. C. Dong and P. Lederer. Characterizations of sequential valuation rules. In Proceedings of the 22nd International Conference on Autonomous Agents and Multiagent Systems (AAMAS), pages 1697-1705, 2023. [ link | pdf ]
  8. T. Delemazure, T. Demeulemeester, M. Eberl, J. Israel, and P. Lederer. Strategyproofness and proportionality in party-approval multiwinner elections. In Proceedings of the 37th AAAI Conference on Artificial Intelligence (AAAI), pages 5591-5599, 2023. [ link | pdf ]
  9. F. Brandt, P. Lederer, and S. Tausch. Strategyproof social decision schemes on super Condorcet domains. In Proceedings of the 22nd International Conference on Autonomous Agents and Multiagent Systems (AAMAS), pages 1734-1742, 2023. [ link | pdf ]
  10. T. Delemazure, T. Demeulemeester, M. Eberl, J. Israel, and P. Lederer. The incompatibility of strategy-proofness and representation in party-approval multi-winner elections. Archive of Formal Proofs, 2022. [ link ]
  11. F. Brandt, P. Lederer, and W. Suksompong. Incentives in social decision schemes with pairwise comparison preferences. In Proceedings of the 31st International Joint Conference on Artificial Intelligence (IJCAI), pages 130-136, 2022. [ link | pdf ]
  12. F. Brandt, P. Lederer, and R. Romen. Relaxed notions of Condorcet-consistency and efficiency for strategyproof social decision schemes. In Proceedings of the 21st International Conference on Autonomous Agents and Multiagent Systems (AAMAS), pages 181-189, 2022. [ link | pdf ]
  13. P. Lederer. Strategyproof randomized social choice for restricted sets of utility functions. In Proceedings of the 30th International Joint Conference on Artificial Intelligence (IJCAI), pages 306-312, 2021. [ link | pdf ]
  14. P. Lederer. Non-manipulability in set-valued and probabilistic social choice theory (doctoral consortium). In Proceedings of the 20th International Conference on Autonomous Agents and Multiagent Systems (AAMAS), pages 1823-1825, 2021. [ link | pdf ]
  15. F. Brandt, M. Bullinger, and P. Lederer. On the indecisiveness of Kelly-strategyproof social choice functions. In Proceedings of the 20th International Conference on Autonomous Agents and Multiagent Systems (AAMAS), pages 251-259, 2021. [ link | pdf ]
Theses
  1. P. Lederer. Strategic manipulation in social choice theory. PhD thesis, Technical University of Munich, 2024. [ link | pdf ]
  2. P. Lederer. Kelly-Strategyproof Social Choice Functions. Master's thesis, Technical University of Munich, 2020. [ pdf ]

Teaching

Courses
Student projects
  • Honour's thesis Axiomatic properties in proportional multi-winner ranked voting (Angus Ritossa, 2024)
  • Master's thesis ε‐Strategyproofness Social Decision Schemes (Jonathan Stein, 2024)
  • Master's thesis Strategyproofness in Approval-based Committee Elections: Domain Restrictions and Iterative Voting (Evghenii Beriozchin, 2024)
  • Interdisciplinary Project A Quantitative Analysis of Set Extensions for Social Choice Theory (Ahmet Semiz, 2023)
  • Master's thesis Metric Distortion in Randomized Social Choice (Fabian Frank, 2023)
  • Bachelor's thesis Modeling Utility Functions in Social Choice Theory (Michelle Heinz, 2022)
  • Bachelor's thesis Random Assignment with Pairwise Comparison Preferences (Patryk Morawski, 2022)
  • Master's thesis Understanding the SD impossibiliy theorem (Alexander Thole, 2021)
  • Master's thesis Characterizing the Condorcet Rule (Sascha Tausch, 2021)
  • Master's thesis Non-manipulable Social Desicision Schemes (Rene Romen, 2020)

Community Service

Refereeing Conferences and Workshops
Refereeing Journals
  • Journal of Artificial Intelligence Research (JAIR)
  • Theoretical Economics (TE) [as subreviewer]
  • Games and Economic Behavior (GEB)
  • Social Choice and Welfare (SCW)
  • Journal of Autonomous Agents and Multi-Agent Systems (JAAMAS)
  • AMS Contemporary Mathematics Series (CMS)
  • Mathematical Social Sciences (MSS)
  • Theory of Computing Systems (ToCS)
  • Artificial Intelligence (AIJ)
  • Review of Economic Design (RoED)
  • Discrete Applied Mathematics (DAM)
  • Annals of Mathematics and Artificial Intelligence (Ann. Math. Artif. Intell.)
  • Journal of Law and Economics (JLE)
  • Journal of Mathematical Economics (JME)
  • Economics Letters (Econ. Lett.)