Strengthening Proportionality in Temporal Voting

Bradley Phillips; Edith Elkind; Nicholas Teh; Tomasz W\k{a}s

REVIEW 1 major objections 4 minor 50 references

Strengthening Proportionality in Temporal Voting

T0 review · 1 major / 4 minor · reviewed 2026-08-07 · deepseek-v4-flash

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Pith's one-line read Temporal elections always admit outcomes satisfying the strong proportionality axioms EJR+ and FJR.

desk verdict A solid and genuinely new map of temporal proportionality axioms, with an isolated and likely fixable citation-direction glitch in the EJR+ satisfiability proof. read the letter →

arxiv 2505.22513 v1 pith:NLJO34HR submitted 2025-05-28 cs.GT cs.AI

Bradley Phillips , Edith Elkind , Nicholas Teh , Tomasz Wąs This is my paper

classification cs.GTcs.AI MSC 91B1291B14

keywords temporalvotingproportionalrepresentationjustifiedextendedrepresentation+fullapprovalballotsgreedycohesiveruleepsilon-lsPAV

verification ladder T0 review T1 audit T2 compute T3 formal

The pith

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The reading

This paper extends justified-representation axioms for multiwinner approval voting to settings where one candidate is selected in each of several rounds, and asks which proportionality guarantees can always be met. It introduces temporal versions of EJR+, FJR, full proportional JR, and core stability, and shows that two of them — temporal EJR+ and temporal FJR — are satisfiable in every temporal election. The paper also proves that an EJR+ outcome can be computed in polynomial time, whereas FJR outcomes exist but are not known to be polynomial-time computable. It maps which axioms imply which, including explicit non-implications, giving a hierarchy of proportionality concepts in the temporal setting.

What carries the argument

The paper's central objects are $(\sigma, \tau)$-cohesive groups of voters: a set $S$ is $(\sigma, \tau)$-cohesive if in a chosen set of $\tau$ rounds, at least $\sigma$ voters in $S$ approve the same candidate in each round. This local cohesion measure replaces the group size $|S|$ in the demand calculation, and it is what makes temporal EJR+ satisfiable. The two rules doing the heavy lifting are $\varepsilon$-lsPAV, a local-search variant of proportional approval voting that maximizes the harmonic score, and a modified Greedy Cohesive Rule that partitions voters by their maximum achievable demand $\mu_S(T)$ and allocates rounds to each part. For sFPJR, the Serial Dictatorship Rule works when the number of rounds is a multiple of the number of voters.

What would settle it

Run $\varepsilon$-lsPAV with $\varepsilon = 1/(3\ell^2)$ on an arbitrary temporal election and check whether the output satisfies EJR+ by the paper's polynomial-time verifier; a single output violating EJR+ would contradict Theorem 3.9. Alternatively, an explicit temporal election for which the Greedy Cohesive Rule of Algorithm 1 returns an outcome violating FJR would falsify Theorem 4.5.

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Extended reading notes

Core claim

The central claim is that the temporal setting, in which exactly one candidate is selected per round, still admits the strong proportionality axioms EJR+ and FJR. For EJR+, the paper shows that the temporal $\varepsilon$-lsPAV rule, with $\varepsilon < 1/\ell^2$, always returns an EJR+ outcome (Theorem 3.9), and that EJR+ implies temporal EJR and is polynomial-time verifiable. For FJR, a variant of the Greedy Cohesive Rule outputs an FJR outcome in every temporal election (Theorem 4.5). In contrast, the ‘strong’ versions of these axioms (sEJR+, sFJR) are generally unsatisfiable, and the paper exhibits elections with no sJR outcome, so a useful strengthening requires a careful definition that scales guarantees with the number of voters who agree in a round rather than the whole group size.

Load-bearing premise

The proof that EJR+ is always satisfiable relies on a previously published guarantee that $\varepsilon$-lsPAV with $\varepsilon$ in $[1/(2\ell^2), 1/\ell^2)$ provides temporal EJR; if that guarantee or the stated $\varepsilon$ bounds fail, the EJR+ satisfiability proof would not go through.

Editorial extensions

If this is right

Every temporal election has an outcome satisfying temporal EJR+, and such an outcome can be found in polynomial time.
Every temporal election has an outcome satisfying temporal FJR, though the paper leaves open whether it can be computed in polynomial time.
Strong versions of the axioms (sEJR+, sFJR, sJR) are not generally satisfiable, even when every voter approves exactly one candidate per round.
When the number of rounds is divisible by the number of voters and every voter approves at least one candidate per round, Serial Dictatorship provides sFPJR.
The paper establishes a complete implication map: among the axioms in its hierarchy, one implies another exactly when a path exists in the figure.

Reading between the lines

Editorial extensions of the paper, not claims the author makes directly.

A testable extension: if one restricts to single-peaked or single-crossing profiles, the strong axioms may become satisfiable in cases where the paper shows they fail in general.
The $(\sigma, \tau)$-cohesion idea could be ported to participatory budgeting, where rounds become projects or budget categories, to define stronger proportionality guarantees.
The paper's separation results suggest that any rule satisfying EJR+ and FJR simultaneously would have to combine local-search and greedy-cohesive features; the paper does not propose such a unified rule.
Since EJR+ is polynomial-time verifiable, one could empirically test the gap between EJR+ and FJR by computing both rules on real preference data.

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Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, and a circularity audit.

Desk Editor's Note

read the letter

You should know two things about this paper: it is the best current map of proportionality axioms for temporal voting, and its central EJR+ satisfiability proof contains a citation-direction glitch that is very likely a typo but needs to be checked before relying on it.

What is new: the authors adapt EJR+, FJR, FPJR, and core stability to the temporal setting. The naive strong variants are unsatisfiable, so they introduce (σ,τ)-cohesiveness as a local measure to define a satisfiable EJR+. They prove EJR+ is satisfiable by ε-lsPAV with ε = 1/(2ℓ²), that GCR gives FJR, and that SDR gives sFPJR when n divides ℓ. They also establish a complete implication hierarchy with a dozen separations. That is real work, and it fills a genuine gap: previous temporal voting papers only had JR/PJR/EJR.

The proofs look careful. I did not find a false theorem. The one issue that stands out is in Theorem 3.9, the σ=|S| case. The proof says Chandak et al. [2024, Theorem 4.5] gives ε-lsPAV with ε > 1/ℓ² provides EJR. But the theorem statement and the polynomial-time parameter require ε < 1/ℓ². If that citation is actually for ε < 1/ℓ², it's a one-character fix. If not, the σ=|S| case is unproven for the regime the paper uses. I suspect a typo, because the rest of the proof uses exactly the kind of local improvement argument that works for small ε. Still, the authors need to resolve it — a referee should ask for the precise ε range from Chandak et al. or a direct proof.

The other flagged detail, 'we can assume r∈R', is minor and fixable. The paper is honest about the parts that remain open (poly-time FJR, core satisfiability), which I appreciate.

Who is this for: anyone working on sequential or temporal decision-making, multiwinner approval voting, or the axiomatics of proportionality. It is a theory paper; no data, no parameters. If you work in computational social choice, it deserves a careful read.

My recommendation: yes, send it to peer review. The potential gap is isolated and likely typographical, and the rest is solid. If the ε question is resolved in revision, this becomes a strong paper.

Referee Report

1 major / 4 minor

Summary. This paper studies temporal approval voting, where an outcome is a sequence of one candidate per round, and introduces temporal adaptations of EJR+, FJR, FPJR, and the core, together with weak and strong variants. The main results are: (i) EJR+ always has an outcome, can be checked in polynomial time, and is produced by ε-lsPAV for ε < 1/ℓ² (Proposition 3.7 and Theorem 3.9); (ii) FJR always has an outcome, produced by the Greedy Cohesive Rule, albeit not in polynomial time (Theorem 4.5); (iii) sFPJR is satisfiable in polynomial time by Serial Dictatorship when the number of rounds is a multiple of the number of voters and every ballot is non-empty (Theorem 5.3), while sEJR and sEJR+ are unsatisfiable in general (Proposition 3.4 and Appendix D); and (iv) a comprehensive hierarchy of implications and separations among the axioms is established (Propositions 3.3, 3.6, 4.4, 5.2, 6.2, 7.1). The central claim is that EJR+ and FJR strengthen EJR while remaining satisfiable in every temporal election.

Significance. The paper is a solid contribution to the computational social choice literature on temporal voting. Its main value is mapping the frontier of satisfiable proportionality axioms: it shows that EJR+ and FJR, two strengthenings of EJR from multiwinner voting, can be adapted to the temporal setting while retaining satisfiability, and it gives a rich implication hierarchy with explicit counterexamples. The proofs are detailed and mostly self-contained in the appendix, and the polynomial-time verification algorithm for EJR+ (Proposition 3.7) is a concrete strength. The paper does not fit any result to data and has no free parameters; the design choice of (σ,τ)-cohesiveness is explicitly motivated. If the technical issue in Theorem 3.9 noted below is resolved, the paper will be a valuable reference for future work on temporal proportionality.

major comments (1)

[Section 3, Theorem 3.9] In the σ = |S| case of the proof of Theorem 3.9, the paper cites Chandak et al. [2024, Theorem 4.5] as showing that ε-lsPAV provides EJR for ε > 1/ℓ². However, the theorem being proved assumes ε < 1/ℓ², and the polynomial-time instantiation described just before the theorem uses ε = 1/(2ℓ²), which lies in [1/(2ℓ²), 1/ℓ²), not in (1/ℓ², ∞). The cited range and the proof's assumption are disjoint, so the σ = |S| case is unsupported as written. The authors should correct the inequality to the actual range covered by Chandak et al. (for example, ε < 1/ℓ² or ε ∈ [1/(2ℓ²), 1/ℓ²)), or supply a direct proof for this case. If the cited theorem really covers only ε > 1/ℓ², then the satisfiability claim for EJR+ in every temporal election is not established by the current proof, which directly affects the abstract's central assertion.

minor comments (4)

[Section 3, Theorem 3.9] The sentence 'We can assume r ∈ R, with c_r = c' is not justified on the spot. It is correct: since c is approved by every voter in S in round r, replacing any round of the witnessing set R by r preserves the property that at least σ voters in S approve the chosen candidate in each round. Please add this one-line justification.
[Proposition 3.4 and Appendix F] Several election tables appear corrupted or misaligned in the text, for example the table in Proposition 3.4 and the tables in Proposition F.1 Claims iii and x. The row and column labels do not match the stated numbers of voters and rounds. Please re-typeset these tables so the election data are unambiguous.
[Theorem 5.3] The proof states 'Since each voter selects the outcome of exactly ℓ/n rounds, we have sat_S(o) ≥ ℓ·|S|/n.' This lower bound additionally relies on the fact that the sets of rounds assigned to different voters are disjoint, which holds for SDR because each round is assigned to exactly one voter. Making this disjointness explicit would improve clarity.
[Proposition 3.7] In the verification algorithm, the condition 'if all voters in S_{r,c,λ} approve o_r in round r, we disregard this set' is correct but could be phrased more explicitly: in that case o_r ∈ ∩_{i∈S_{r,c,λ}} a_{i,r}, so this set cannot witness a violation of EJR+.

Circularity Check

0 steps flagged · score 0.0 of 10

No significant circularity: the EJR+ and FJR derivations are self-contained proofs from their respective rules, with only independent prior work cited at one boundary case.

full rationale

The paper's central derivations do not reduce to their inputs. Theorem 3.9 proves that ε-lsPAV with ε < 1/ℓ^2 satisfies EJR+ by assuming a violation and lower-bounding the harmonic-score gain from switching one round to a witness candidate; the contradiction comes from ε-lsPAV's own local optimality. The only invoked external result is Chandak et al. [2024, Theorem 4.5] for the σ=|S| case; that is prior independent work by a disjoint author set, and the implication from EJR violation to a harmonic-score gain is not definitional. The apparent mismatch in the ε inequality direction is a correctness or typographical concern, not a circularity. Theorem 4.5 proves FJR for GCR directly: the algorithm partitions voters using the same demand function μ_S(T) that appears in the FJR definition, but the proof establishes that the greedy choices leave enough rounds and that each voter's final satisfaction reaches the required threshold via the explicit second-phase construction; it does not assume the FJR property. Section 5's sFPJR proof for SDR is an immediate counting argument from the round allocation. Self-citations, such as Elkind et al. [2025c] for the GCR starting point, are contextual and no EJR or FJR guarantee from those papers is used as a load-bearing premise. No fitted parameter is renamed as a prediction, and no known result is repackaged under new coordinates.

Assumptions & free parameters 0 free parameters · 4 assumptions · 0 invented entities

No free parameters or invented physical entities. The only new postulates are axiomatic definitions, which are accounted for as axioms.

assumptions (4)

domain assumption Temporal election model with n voters, ell rounds, one candidate selected per round, and approval ballots per round.
Section 2 defines the model; all results are relative to this framework.
standard math epsilon-lsPAV with epsilon in [1/(2 ell^2), 1/ell^2) runs in polynomial time and provides temporal EJR (Chandak et al. 2024, Aziz et al. 2018).
Invoked in Section 3, Theorem 3.9, to establish both polynomial-time computability and the sigma=|S| case.
domain assumption For the sFPJR satisfiability result, the election is restricted to E>=1 (each voter approves at least one candidate per round) and n divides ell.
Theorem 5.3 uses n|ell and nonempty approval sets so Serial Dictatorship is well-defined and the bound sat_S(o) >= ell*|S|/n holds.
ad hoc to paper The choice of (sigma, tau)-cohesiveness as the correct adaptation of EJR+ is a modeling decision, not a mathematical fact.
Definition 3.5 is introduced to make a satisfiable strengthening; the paper argues for it via implications to EJR and polynomial verifiability, but this is not forced by prior theory.

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Cite this review

Pith. "Pith review of Strengthening Proportionality in Temporal Voting." pith.science (2026). https://pith.science/paper/NLJO34HR

@misc{pith2026250522513,
  author       = {Pith},
  title        = {Pith review of: Strengthening Proportionality in Temporal Voting},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/NLJO34HR}},
  note         = {Machine review of arXiv:2505.22513}
}

read the original abstract

We study proportional representation in the framework of temporal voting with approval ballots. Prior work adapted basic proportional representation concepts -- justified representation (JR), proportional JR (PJR), and extended JR (EJR) -- from the multiwinner setting to the temporal setting. Our work introduces and examines ways of going beyond EJR. Specifically, we consider stronger variants of JR, PJR, and EJR, and introduce temporal adaptations of more demanding multiwinner axioms, such as EJR+, full JR (FJR), full proportional JR (FPJR), and the Core. For each of these concepts, we investigate its existence and study its relationship to existing notions, thereby establishing a rich hierarchy of proportionality concepts. Notably, we show that two of our proposed axioms -- EJR+ and FJR -- strengthen EJR while remaining satisfiable in every temporal election.

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Works this paper leans on

50 extracted references · 39 canonical work pages

[1]

Fair allocation over time, with applications to content moderation

Amine Allouah, Christian Kroer, Xuan Zhang, Vashist Avadhanula, Nona Bohanon, Anil Dania, Caner Gocmen, Sergey Pupyrev, Parikshit Shah, Nicolas Stier-Moses, and Ken Rodr\' guez Taarup. Fair allocation over time, with applications to content moderation. In Proceedings of the 29th ACM SIGKDD Conference on Knowledge Discovery and Data Mining (KDD), pages 25-...

work page 2023
[2]

Better collective decisions via uncertainty reduction

Shiri Alouf-Heffetz, Laurent Bulteau, Edith Elkind, Nimrod Talmon, and Nicholas Teh. Better collective decisions via uncertainty reduction. In Proceedings of the 31st International Joint Conference on Artificial Intelligence (IJCAI), pages 24--30, 2022

work page 2022
[3]

The expanding approvals rule: Improving proportional representation and monotonicity

Haris Aziz and Barton E Lee. The expanding approvals rule: Improving proportional representation and monotonicity. Social Choice and Welfare, 54 0 (1): 0 1--45, 2020

work page 2020
[4]

Justified representation in approval-based committee voting

Haris Aziz, Markus Brill, Vincent Conitzer, Edith Elkind, Rupert Freeman, and Toby Walsh. Justified representation in approval-based committee voting. Social Choice and Welfare, 48: 0 461--485, 2017

work page 2017
[5]

On the complexity of extended and proportional justified representation

Haris Aziz, Edith Elkind, Shenwei Huang, Martin Lackner, Luis S\' a nchez-Fern\' a ndez, and Piotr Skowron. On the complexity of extended and proportional justified representation. In Proceedings of the 32nd AAAI Conference on Artificial Intelligence (AAAI), pages 902--909, 2018

work page 2018
[6]

Fair resource allocation over time

Evripidis Bampis, Bruno Escoffier, and Sasa Mladenovic. Fair resource allocation over time. In Proceedings of the 17th International Conference on Autonomous Agents and Multi-Agent Systems (AAMAS), pages 766--773, 2018

work page 2018
[7]

Approval-based committee voting in practice: A case study of (over-)representation in the polkadot blockchain

Niclas Boehmer, Markus Brill, Alfonso Cevallos, Jonas Gehrlein, Luis S\'anchez-Fern\'andez, and Ulrike Schmidt-Kraepelin. Approval-based committee voting in practice: A case study of (over-)representation in the polkadot blockchain. In Proceedings of the 38th AAAI Conference on Artificial Intelligence (AAAI), pages 9519--9527, 2024

work page 2024
[8]

Procaccia

Niclas Boehmer, Sara Fish, and Ariel D. Procaccia. Generative social choice. In Proceedings of the 42nd International Conference on Machine Learning (ICML), 2025

work page 2025

Show all 50 references

[9]

An experimental view on committees providing justified representation

Robert Bredereck, Piotr Faliszewski, Andrzej Kaczmarczyk, and Rolf Niedermeier. An experimental view on committees providing justified representation. In Proceedings of the 28th International Joint Conference on Artificial Intelligence (IJCAI), pages 109--115, 2019

2019
[10]

Electing successive committees: Complexity and algorithms

Robert Bredereck, Andrzej Kaczmarczyk, and Rolf Niedermeier. Electing successive committees: Complexity and algorithms. In Proceedings of the 34th AAAI Conference on Artificial Intelligence (AAAI), pages 1846--1853, 2020

2020
[11]

When votes change and committees should (not)

Robert Bredereck, Till Fluschnik, and Andrzej Kaczmarczyk. When votes change and committees should (not). In Proceedings of the 31st International Joint Conference on Artificial Intelligence (IJCAI), pages 144--150, 2022

2022
[12]

Robust and verifiable proportionality axioms for multiwinner voting

Markus Brill and Jannik Peters. Robust and verifiable proportionality axioms for multiwinner voting. In Proceedings of the 24th ACM Conference on Economics and Computation (EC), page 301, 2023

2023
[13]

Approval-based apportionment

Markus Brill, Paul Gölz, Dominik Peters, Ulrike Schmidt-Kraepelin, and Kai Wilker. Approval-based apportionment. Mathematical Programming, 203: 0 77--105, 2024

2024
[14]

Justified representation for perpetual voting

Laurent Bulteau, Noam Hazon, Rutvik Page, Ariel Rosenfeld, and Nimrod Talmon. Justified representation for perpetual voting. IEEE Access, 9: 0 96598--96612, 2021

2021
[15]

Overview of polkadot and its design considerations

Jeff Burdges, Alfonso Cevallos, Peter Czaban, Rob Habermeier, Syed Hosseini, Fabio Lama, Handan Kilin c Alper, Ximin Luo, Fatemeh Shirazi, Alistair Stewart, and Gavin Wood. Overview of polkadot and its design considerations. arXiv preprint arXiv:2005.13456, 2020

2005 arXiv
[16]

A verifiably secure and proportional committee election rule

Alfonso Cevallos and Alistair Stewart. A verifiably secure and proportional committee election rule. In Proceedings of the 3rd ACM Conference on Advances in Financial Technologies (AFT), pages 29--42, 2021

2021
[17]

Proportional aggregation of preferences for sequential decision making

Nikhil Chandak, Shashwat Goel, and Dominik Peters. Proportional aggregation of preferences for sequential decision making. In Proceedings of the 38th AAAI Conference on Artificial Intelligence (AAAI), pages 9573--9581, 2024

2024
[18]

Multi-winner reconfiguration

Jiehua Chen, Christian Hatschka, and Sofia Simola. Multi-winner reconfiguration. In Proceedings of the 37th International Conference on Neural Information Processing Systems (NeurIPS), pages 85899--85931, 2024

2024
[19]

Fair public decision making

Vincent Conitzer, Rupert Freeman, and Nisarg Shah. Fair public decision making. In Proceedings of the 18th ACM Conference on Economics and Computation (EC), pages 629--646, 2017

2017
[20]

Strategyproofness and proportionality in party-approval multiwinner elections

Th\'eo Delemazure, Tom Demeulemeester, Manuel Eberl, Jonas Israel, and Patrick Lederer. Strategyproofness and proportionality in party-approval multiwinner elections. In Proceedings of the 37th AAAI Conference on Artificial Intelligence (AAAI), pages 5591--5599, 2023

2023
[21]

Algorithmics of egalitarian versus equitable sequences of committees

Eva Michelle Deltl, Till Fluschnik, and Robert Bredereck. Algorithmics of egalitarian versus equitable sequences of committees. In Proceedings of the 32nd International Joint Conference on Artificial Intelligence (IJCAI), pages 2651--2658, 2023

2023
[22]

Fairness in temporal slot assignment

Edith Elkind, Sonja Kraiczy, and Nicholas Teh. Fairness in temporal slot assignment. In Proceedings of the 15th International Symposium on Algorithmic Game Theory (SAGT), pages 490--507, 2022

2022
[23]

Temporal elections: Welfare, strategyproofness, and proportionality

Edith Elkind, Tzeh Yuan Neoh, and Nicholas Teh. Temporal elections: Welfare, strategyproofness, and proportionality. In Proceedings of the 27th European Conference on Artificial Intelligence (ECAI), pages 3292--3299, 2024 a

2024
[24]

Temporal fairness in multiwinner voting

Edith Elkind, Svetlana Obraztsova, and Nicholas Teh. Temporal fairness in multiwinner voting. In Proceedings of the 38th AAAI Conference on Artificial Intelligence (AAAI), pages 22633--22640, 2024 b

2024
[25]

Temporal fair division of indivisible items

Edith Elkind, Alexander Lam, Mohamad Latifian, Tzeh Yuan Neoh, and Nicholas Teh. Temporal fair division of indivisible items. In Proceedings of the 24th International Conference on Autonomous Agents and Multiagent Systems (AAMAS), pages 676--685, 2025 a

2025
[26]

Not in my backyard! T emporal voting over public chores

Edith Elkind, Tzeh Yuan Neoh, and Nicholas Teh. Not in my backyard! T emporal voting over public chores. In Proceedings of the 34th International Joint Conference on Artificial Intelligence (IJCAI), 2025 b

2025
[27]

Verifying proportionality in temporal voting

Edith Elkind, Svetlana Obraztsova, Jannik Peters, and Nicholas Teh. Verifying proportionality in temporal voting. In Proceedings of the 39th AAAI Conference on Artificial Intelligence (AAAI), pages 13805--13813, 2025 c

2025
[28]

Fair allocation of indivisible public goods

Brandon Fain, Kamesh Munagala, and Nisarg Shah. Fair allocation of indivisible public goods. In Proceedings of the 19th ACM Conference on Economics and Computation (EC), pages 575--592, 2018

2018
[29]

Parkes, Ariel D

Sara Fish, Paul Gölz, David C. Parkes, Ariel D. Procaccia, Gili Rusak, Itai Shapira, and Manuel Wüthrich. Generative social choice. In Proceedings of the 25th ACM Conference on Economics and Computation (EC), page 985, 2024

2024
[30]

Using multiwinner voting to search for movies

Grzegorz Gawron and Piotr Faliszewski. Using multiwinner voting to search for movies. Theory and Decision, 2024

2024
[31]

Full proportional justified representation

Yusuf Hakan Kalayci, Jiasen Liu, and David Kempe. Full proportional justified representation. In Proceedings of the 24th International Conference on Autonomous Agents and Multi-Agent Systems (AAMAS), 2025

2025
[32]

Marc Kilgour

D. Marc Kilgour. Approval Balloting for Multi-winner Elections, pages 105--124. Springer, 2010

2010
[33]

Perpetual voting: F airness in long-term decision making

Martin Lackner. Perpetual voting: F airness in long-term decision making. In Proceedings of the 34th AAAI Conference on Artificial Intelligence (AAAI), pages 2103--2110, 2020

2020
[34]

Proportional decisions in perpetual voting

Martin Lackner and Jan Maly. Proportional decisions in perpetual voting. In Proceedings of the 37th AAAI Conference on Artificial Intelligence (AAAI), pages 5722--5729, 2023

2023
[35]

Multi-Winner Voting with Approval Preferences

Martin Lackner and Piotr Skowron. Multi-Winner Voting with Approval Preferences. Springer, 2023

2023
[36]

A generalised theory of proportionality in collective decision making

Tom \'a s Masa r \' k, Grzegorz Pierczy \'n ski, and Piotr Skowron. A generalised theory of proportionality in collective decision making. In Proceedings of the 25th ACM Conference on Economics and Computation (EC), pages 734--754, 2024

2024
[37]

Patro, Prithwish Jana, Abhijnan Chakraborty, Krishna P

Gourab K. Patro, Prithwish Jana, Abhijnan Chakraborty, Krishna P. Gummadi, and Niloy Ganguly. Scheduling virtual conferences fairly: Achieving equitable participant and speaker satisfaction. In Proceedings of the 2022 ACM Web Conference (WWW), pages 2646--2656, 2022

2022
[38]

Proportional representation for artificial intelligence

Dominik Peters. Proportional representation for artificial intelligence. In Proceedings of the 27th European Conference on Artificial Intelligence (ECAI), pages 27--31, 2024

2024
[39]

Proportionality and the limits of welfarism

Dominik Peters and Piotr Skowron. Proportionality and the limits of welfarism. In Proceedings of the 21st ACM Conference on Economics and Computation (EC), pages 793--794, 2020

2020
[40]

Proportional participatory budgeting with additive utilities

Dominik Peters, Grzegorz Pierczy\' n ski, and Piotr Skowron. Proportional participatory budgeting with additive utilities. In Proceedings of the 35th International Conference on Neural Information Processing Systems (NeurIPS), pages 12726--12737, 2021

2021
[41]

orsm l 25 . Lars H\

Edvard Phragm \'e n. Proportionella val. en valteknisk studie. In Svenska sp\"orsm l 25 . Lars H\"okersbergs f \"o rlag, Stockholm, 1895
[42]

Representative ranking for deliberation in the public sphere

Manon Revel, Smitha Milli, Tyler Lu, Jamelle Watson - Daniels, and Max Nickel. Representative ranking for deliberation in the public sphere. In Proceedings of the 42th International Conference on Machine Learning (ICML), 2025

2025
[43]

Proportional justified representation

Luis S\' a nchez-Fern\' a ndez, Edith Elkind, Martin Lackner, Norberto Fern\' a ndez, Jes\' u s Fisteus, Pablo Basanta Val, and Piotr Skowron. Proportional justified representation. In Proceedings of the 31st AAAI Conference on Artificial Intelligence (AAAI), pages 670--676, 2017

2017
[44]

Strategy-proof allocation mechanisms at differentiable points

Mark A Satterthwaite and Hugo Sonnenschein. Strategy-proof allocation mechanisms at differentiable points. The Review of Economic Studies, 48 0 (4): 0 587--597, 1981

1981
[45]

Proportional public decisions

Piotr Skowron and Adrian G\' o recki. Proportional public decisions. In Proceedings of the 36th AAAI Conference on Artificial Intelligence (AAAI), pages 5191--5198, 2022

2022
[46]

Preference aggregation mechanisms for a tourism-oriented B ayesian recommender

Errikos Streviniotis and Georgios Chalkiadakis. Preference aggregation mechanisms for a tourism-oriented B ayesian recommender. In Proceedings of the 23rd International Conference on Principles and Practice of Multi-Agent Systems (PRIMA), pages 331--346, 2022

2022
[47]

Jizhou Wu, Jianye Hao, Tianpei Yang, Xiaotian Hao, Yan Zheng, Weixun Wang, and Matthew E. Taylor. Portal: Automatic curricula generation for multiagent reinforcement learning. In Proceedings of the 38th AAAI Conference on Artificial Intelligence (AAAI), pages 15934--15942, 2024

2024
[48]

Yaodong Yang, Jun Luo, Ying Wen, Oliver Slumbers, Daniel Graves, Haitham Bou Ammar, Jun Wang, and Matthew E. Taylor. Diverse auto-curriculum is critical for successful real-world multiagent learning systems. In Proceedings of the 20th International Conference on Autonomous Age...

2021
[49]

Multiwinner temporal voting with aversion to change

Valentin Zech, Niclas Boehmer, Edith Elkind, and Nicholas Teh. Multiwinner temporal voting with aversion to change. In Proceedings of the 27th European Conference on Artificial Intelligence (ECAI), pages 3236--3243, 2024

2024
[50]

write newline

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[1] [1]

Fair allocation over time, with applications to content moderation

Amine Allouah, Christian Kroer, Xuan Zhang, Vashist Avadhanula, Nona Bohanon, Anil Dania, Caner Gocmen, Sergey Pupyrev, Parikshit Shah, Nicolas Stier-Moses, and Ken Rodr\' guez Taarup. Fair allocation over time, with applications to content moderation. In Proceedings of the 29th ACM SIGKDD Conference on Knowledge Discovery and Data Mining (KDD), pages 25-...

work page 2023

[2] [2]

Better collective decisions via uncertainty reduction

Shiri Alouf-Heffetz, Laurent Bulteau, Edith Elkind, Nimrod Talmon, and Nicholas Teh. Better collective decisions via uncertainty reduction. In Proceedings of the 31st International Joint Conference on Artificial Intelligence (IJCAI), pages 24--30, 2022

work page 2022

[3] [3]

The expanding approvals rule: Improving proportional representation and monotonicity

Haris Aziz and Barton E Lee. The expanding approvals rule: Improving proportional representation and monotonicity. Social Choice and Welfare, 54 0 (1): 0 1--45, 2020

work page 2020

[4] [4]

Justified representation in approval-based committee voting

Haris Aziz, Markus Brill, Vincent Conitzer, Edith Elkind, Rupert Freeman, and Toby Walsh. Justified representation in approval-based committee voting. Social Choice and Welfare, 48: 0 461--485, 2017

work page 2017

[5] [5]

On the complexity of extended and proportional justified representation

Haris Aziz, Edith Elkind, Shenwei Huang, Martin Lackner, Luis S\' a nchez-Fern\' a ndez, and Piotr Skowron. On the complexity of extended and proportional justified representation. In Proceedings of the 32nd AAAI Conference on Artificial Intelligence (AAAI), pages 902--909, 2018

work page 2018

[6] [6]

Fair resource allocation over time

Evripidis Bampis, Bruno Escoffier, and Sasa Mladenovic. Fair resource allocation over time. In Proceedings of the 17th International Conference on Autonomous Agents and Multi-Agent Systems (AAMAS), pages 766--773, 2018

work page 2018

[7] [7]

Approval-based committee voting in practice: A case study of (over-)representation in the polkadot blockchain

Niclas Boehmer, Markus Brill, Alfonso Cevallos, Jonas Gehrlein, Luis S\'anchez-Fern\'andez, and Ulrike Schmidt-Kraepelin. Approval-based committee voting in practice: A case study of (over-)representation in the polkadot blockchain. In Proceedings of the 38th AAAI Conference on Artificial Intelligence (AAAI), pages 9519--9527, 2024

work page 2024

[8] [8]

Procaccia

Niclas Boehmer, Sara Fish, and Ariel D. Procaccia. Generative social choice. In Proceedings of the 42nd International Conference on Machine Learning (ICML), 2025

work page 2025