Reconfiguring Proportional Committees

Chris Dong; Fabian Frank; Jannik Peters; Warut Suksompong

REVIEW 1 major objections 5 minor 1 cited by

Reconfiguring Proportional Committees

T0 review · 1 major / 5 minor · reviewed 2026-08-16 · deepseek-v4-flash

Challenge this review Re-run · record.json Download PDF Read on arXiv ↗ Review JSON

Pith's one-line read The set of committees satisfying justified representation is not always connected, and deciding whether two such committees are connected is PSPACE-complete.

desk verdict Opens a genuinely new subarea—reconfiguration under proportionality axioms—and the main structural results appear sound; worth a careful referee. read the letter →

arxiv 2504.15157 v1 pith:DDXIEH7T submitted 2025-04-21 cs.GT

Chris Dong , Fabian Frank , Jannik Peters , Warut Suksompong This is my paper · ORCID

classification cs.GT MSC 91B1268Q1791B14

keywords approval-basedmultiwinnervotingjustifiedrepresentationextendedreconfigurationcommitteeconnectivityPSPACE-completenessproportionalrulesrestrictedpreferencedomains

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 asks whether a proportional committee can be transformed into another by swapping one candidate at a time while every intermediate committee remains proportional. The central answer for the standard axiom of justified representation (JR) is negative: some instances have JR committees that cannot be joined by a path of JR committees, and deciding whether two given JR committees are connected is PSPACE-complete. The negative result is tight and is accompanied by a positive one: any two JR committees can be joined through committees that satisfy a 2-approximation of JR (with the factor 2 optimal), and any two EJR committees can be joined through 4-EJR committees. For seven established voting rules the selected committees all lie in the same connected component of the JR graph, so the obstruction concerns weakly proportional committees rather than the rules used in practice. On candidate-interval and voter-interval preference domains, the set of JR committees is always connected.

What carries the argument

The central object is the graph whose vertices are size-$k$ committees and whose edges connect committees differing in one candidate; a reconfiguration path is legal when every vertex satisfies the chosen proportionality axiom. The positive constructions rely on two structural devices: 2-JR greedy subcommittees, built by repeatedly adding a candidate that covers at least $2n/k$ previously uncovered voters, which every JR committee can reach in at most $k/2$ swaps; and affordable subcommittees, those for which every candidate can be paid for by voters each spending at most $k/n$ total budget, which connect the outputs of the studied voting rules. The PSPACE-hardness proof encodes a SAT instance's assignments as committees so that a legal swap corresponds exactly to a satisfying bit flip.

What would settle it

Exhaustively search all approval profiles with $k=4$ and up to, say, twelve voters for two JR committees with no path of $2$-JR committees between them; an example would refute Theorem 3.7. For the EJR statement, search for a profile with no $4$-EJR subcommittee of size $\lfloor k/4\rfloor$; this would contradict the external lemma on which Theorem 3.9 depends.

Watch

Extended reading notes

Core claim

The paper establishes a sharp phase transition in the swap graph of committees. Exact JR and EJR proportionality do not guarantee connectivity: Theorem 3.1 constructs, for every $k \ge 3$, a profile with a JR committee whose closest other JR committee is at distance $k-1$, and Corollary 3.2 transfers the isolation to EJR. Deciding connectivity among JR committees is PSPACE-complete (Theorem 3.4), by reduction from SAT-Reconfiguration. Yet Theorem 3.7 shows any two JR committees can be connected by at most $2k$ swaps using only $2$-JR committees, and Proposition 3.8 shows no $\alpha < 2$ works. The analogous EJR result uses $4$-EJR (Theorem 3.9). In addition, Theorem 4.5 shows that the outputs of PAV, MES, sequential-Phragmén, GJCR, GreedyEJR, sequential-CCAV, and CCAV are mutually connected within JR, and Theorems 5.1 and 5.2 show full JR connectivity on the candidate-interval and voter-interval domains.

Load-bearing premise

The load-bearing premise is that two cited results borrowed from other papers are correct: that every profile has a small committee meeting 4-EJR, and that affordable subcommittees behave as claimed, because the corresponding theorems here are proved by appeal to them rather than from scratch.

Editorial extensions

If this is right

Any two JR committees have a reconfiguration path of at most $2k$ swaps whose intermediate committees satisfy $2$-JR, and this approximation factor cannot be improved below $2$.
No polynomial-time algorithm can decide whether a JR-only path exists between two given JR committees unless PSPACE collapses to P.
The committees selected by PAV, MES, sequential-Phragmén, GJCR, GreedyEJR, sequential-CCAV, and CCAV are pairwise connected inside the set of JR committees for the same instance.
On candidate-interval and voter-interval domains every pair of JR committees is connected by a JR path, and on the candidate-interval domain the path can be chosen to have length exactly the symmetric difference of the two committees.
JR committees can be isolated up to distance $k-2$ from every other JR committee, so exact-JR constraints alone do not guarantee any nearby alternative committee.

Reading between the lines

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

The PSPACE-completeness result suggests that any practical system that must preserve exact JR while updating a committee will need domain restrictions, approximation slack, or rule-specific structure; the paper's restricted-domain results identify where exact paths survive.
The 2-JR and 4-JR connectivity results imply a simple implementation recipe for platform-style updates: cap the number of swaps at $O(k)$ and accept bounded representation loss, and the transition can be found by local search rather than a global solver.
The contrast between isolated JR committees and the connected choice sets of standard rules points to a possible new axiom: a proportional committee is 'strong' only if it is not isolated in the JR graph, which would rank the weak committees produced by Theorem 3.1 as proportionally deficient.
A direct open extension suggested by the paper's constants is whether the EJR connectivity factor can be lowered from $4$ to $2$; the modified PAV-score technique used in Theorem 3.9 gives a concrete avenue for testing that.

Share X Bluesky LinkedIn Reddit HN

Signed reviews

No signed human review yet.

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

Short version: this paper is the first to ask what happens when you reconfigure between proportional committees while preserving proportionality along the way, and it answers the question for the main axioms with a satisfying mix of hardness, possibility, and rule-specific results. If the details check out, it will be a standard reference.

The new results are real. Theorem 3.1's construction of a JR committee isolated at distance k-2 is neat, and the upper bound in Proposition 3.3 shows it is tight. The PSPACE-completeness reduction from SAT-Reconfiguration is careful—the dummy candidates and literal-swap constraints are doing real work, and I did not find a hole. On the positive side, the fact that any two JR committees are connected via 2-JR committees, and that the factor 2 is tight, is a clean theorem. The EJR analogue with 4-EJR is heavier but the proof strategy (modified PAV score with telescoping) is coherent. The voting-rules part is also strong: it shows that PAV, MES, seq-Phragmén, and friends all land in the same JR-connected component, which nicely contrasts with the general disconnectedness. The restricted-domain results (CI and VI) round out the picture.

The soft spots are minor but should be fixed. In Theorem 3.1, the existence of a size-k C2 committee covering all N2 voters is asserted with 'one can check' instead of a proof; it's true, but needs a sentence. Theorem 3.9 has a typo in the integral bound—the harmonic difference should be bounded by ln(k)-ln(k-r), and the displayed inequality has the limit signs slightly off. More importantly, Section 2's formal definition of α-JR and α-EJR literally says an α-cohesive group must share α common candidates, but the proofs (and Proposition 3.8) use the standard 'α-large and 1-cohesive' interpretation. That ambiguity is confusing and should be corrected; it doesn't affect the α=1 results or the approximation theorems once the intended definition is clear.

The reliance on external lemmas—Dong et al. 2025 for 4-EJR subcommittees, Brill and Peters 2024 for affordability—is fine, they are published results, but I would ask the authors to state them precisely so readers can verify.

Overall this is a well-executed paper that deserves serious refereeing. The central claims survive scrutiny. I'd take it to a seminar and I'd expect it to be accepted after minor revisions.

Referee Report

1 major / 5 minor

Summary. The paper studies reconfiguration of approval-based multiwinner committees under proportionality constraints. Two committees are adjacent when they differ by one candidate, and a committee satisfies JR (resp. EJR) if every 1-cohesive (resp. ℓ-cohesive) voter group is 'represented' in the appropriate sense. The main results are: (i) for every k≥3 there is an instance with a JR committee that is (k−2)-isolated among JR committees, and this bound is tight; (ii) deciding connectivity of two JR committees in the JR graph is PSPACE-complete; (iii) any two JR committees can be connected through 2-JR committees, with the factor 2 tight; (iv) any two EJR committees can be connected through 4-EJR committees; (v) committees returned by MES, seq-Phragmén, PAV, CCAV, seq-CCAV, GJCR, and GreedyEJR all lie in the same connected component of the JR graph; and (vi) on voter-interval and candidate-interval domains the JR graph is connected, with shortest-path connectivity in the CI case and in the Pareto-dominated-free VI case. The proofs combine counting arguments, a reduction from SAT-Reconfiguration, monotonicity and affordability arguments, and domain-specific interval arguments.

Significance. If the results stand, the paper makes a substantial contribution to the young literature on multiwinner reconfiguration. It gives the first impossibility and PSPACE-hardness results for proportionality-preserving transitions, and it offsets these with a clean positive result (2-JR connectivity) whose constant is proved tight. The section on voting rules is valuable: it shows that the isolation phenomenon of Theorem 3.1 is not realized by any of the standard proportional rules, since their output committees are all mutually reachable through JR committees. The restricted-domain results are also natural and give a complete picture for JR on CI and VI instances. A particular strength is that the central constructions, especially the isolation instance and the PSPACE-completeness reduction, are self-contained and the counting arguments check out. The paper does rely on two nontrivial external lemmas (Dong et al.'s 4-EJR subcommittee lemma and Brill and Peters' affordability observations); these are cited but not re-proved, so the corresponding theorems inherit whatever risk attaches to those sources.

major comments (1)

[Section 2, definitions of α-JR and α-EJR] The definition of α-JR is inconsistent with the rest of the paper and with standard usage. The text says a committee satisfies α-JR if 'for every α-cohesive group of voters N′' there is a represented voter, and α-cohesive is defined to mean α-large and sharing at least α common candidates. Similarly, α-EJR is defined with respect to '(αℓ)-cohesive' groups. This is not the notion used in the proofs: Lemma 3.6 and Theorem 3.7 rely on groups that are 2-large and 1-cohesive, and Proposition 3.8 constructs a violating group of size 2r = α n/k that shares a single common candidate. Under the literal wording, that group is not α-cohesive for α>1, so the proof of Proposition 3.8 does not establish a violation. The same issue affects the statements of Theorems 3.7 and 3.9. Please replace the definitions with the standard ones: α-JR means that every group that is α-large and 1-cohesive has a represented voter, and α-EJR means that every group that is αℓ-large and ℓ-cohesive has a voter with at least ℓ approved committee candidates. The α=1 case is unchanged, but all approximate-connectivity claims depend on this correction.

minor comments (5)

[Proof of Theorem 3.1] The sentence 'one can check that any subset of C2 that covers all voters in N2 indeed satisfies JR, and that such a subset of size k exists' should be replaced by an explicit argument. For example, take k candidates from C2 with pairwise distinct missing voters in N2; every N2 voter then approves k−1 of the chosen candidates, and every 1-cohesive group either contains such an N2 voter or is not a support set of a C2 candidate, so JR is satisfied.
[Abstract and Section 1] The string 'PSP ACE' appears with a spurious space in the abstract and in the body; it should read 'PSPACE'.
[Proof of Theorem 3.9, final paragraph] The final transition sequence re-uses the labels d1,...,ds for witness candidates and then labels the members of W4-EJR as d_{s+1},..., while the deletion process might itself introduce additional witness candidates that would naturally receive those same labels. Please make the labeling of process witnesses and target-subcommittee candidates disjoint, or state explicitly that the d_i in W^i are an arbitrary enumeration of the additions in each step.
[Proof of Theorem 5.1] In the case analysis for the shared candidate c of v and v′, the possibility c=ey is not mentioned. If c=ey, then v′ approves ey∈W∗, so the group is represented; this case should be stated to make the argument complete.
[Section 4, Lemmas 4.6–4.8] The paper would benefit from a sentence in the text of Section 4 reminding the reader that the affordability results of Brill and Peters are used not only for MES and GJCR but also for the seq-Phragmén and seq-CCAV arguments in Lemma 4.6, so that the dependence on external results is visible at the point of use.

Circularity Check

0 steps flagged · score 0.0 of 10

No circularity detected: the paper's central results are derived from explicit constructions and independent prior lemmas, not from fitted parameters or self-referential definitions.

full rationale

The paper's principal claims—the existence of (k−2)-isolated JR committees (Theorem 3.1), PSPACE-completeness of JR-reconfiguration (Theorem 3.4), and the 2-JR / 4-EJR connectivity theorems (Theorems 3.7 and 3.9)—are established by self-contained counting arguments and explicit reductions, not by assuming their own conclusions. Theorem 3.1 gives a concrete profile and verifies JR isolation by direct counting; Theorem 3.4 reduces from SAT-Reconfiguration and verifies both directions in the text. The external lemmas cited from prior work, notably Dong et al. [2025, Lemma 5.5] used in Theorem 3.9 and Dong et al. [2025, Proposition 4.3] used in Theorem 5.2, are auxiliary published results rather than restatements of this paper's target theorems, and the paper does not fit parameters to data and then relabel them as predictions. The Brill and Peters [2024] affordability observations are likewise imported as independent background, not as the source of the paper's new connectivity results. No self-citation chain is load-bearing: even if the cited 4-EJR-subcommittee lemma were removed, the central JR results and the 2-JR connectivity theorem would stand on their own. The definitional wording of α-JR/α-EJR in Section 2 is internally inconsistent with the standard interpretation used in the proofs, and the proofs of Proposition 3.8 and related statements rely on the intended 'α-large and 1-cohesive' meaning; this is a correctness-exposition issue, not a circularity issue.

Assumptions & free parameters 0 free parameters · 5 assumptions · 0 invented entities

The paper introduces no free parameters and no new entities. It relies on standard computational complexity facts and on several external results from the prior literature (Brill and Peters on affordability, Dong et al. on 4-EJR subcommittees and VI-CI connection). These external results are cited and used as black boxes.

assumptions (5)

standard math SAT-Reconfiguration is PSPACE-hard (Gopalan et al. 2009).
Used as the basis for the PSPACE-hardness reduction in Theorem 3.4.
standard math Savitch's theorem: PSPACE = NPSPACE.
Used to show membership in PSPACE in Theorem 3.4.
domain assumption Dong et al. 2025, Lemma 5.5: there always exists a subcommittee of size floor(k/4) satisfying 4-EJR.
External lemma cited in Theorem 3.9; the 4-EJR connectivity result depends on it.
domain assumption Definition and properties of affordable committees from Brill and Peters 2024 (e.g., Observation 1: for affordable W, |N_X| >= |X| * n/k for all X subset of W).
Foundation for Proposition 4.4 and Lemmas 4.3 and 4.6; cited, not re-proved.
domain assumption Dong et al. 2025, Proposition 4.3: a VI instance without Pareto-dominated candidates is a CI instance.
Used in Theorem 5.2 to reduce the VI case to CI.

how reviews work

0 comments

Cite this review

Pith. "Pith review of Reconfiguring Proportional Committees." pith.science (2026). https://pith.science/paper/DDXIEH7T

@misc{pith2026250415157,
  author       = {Pith},
  title        = {Pith review of: Reconfiguring Proportional Committees},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/DDXIEH7T}},
  note         = {Machine review of arXiv:2504.15157}
}

abstract

An important desideratum in approval-based multiwinner voting is proportionality. We study the problem of reconfiguring proportional committees: given two proportional committees, is there a transition path that consists only of proportional committees, where each transition involves replacing one candidate with another candidate? We show that the set of committees satisfying the proportionality axiom of justified representation (JR) is not always connected, and it is PSPACE-complete to decide whether two such committees are connected. On the other hand, we prove that any two JR committees can be connected by committees satisfying a $2$-approximation of JR. We also obtain similar results for the stronger axiom of extended justified representation (EJR). In addition, we demonstrate that the committees produced by several well-known voting rules are connected or at least not isolated, and investigate the reconfiguration problem in restricted preference domains.

Figures

Figures reproduced from arXiv: 2504.15157 by the authors.

**Figure 2.** A visualization of Example 2. Voters are depicted a [PITH_FULL_IMAGE:figures/full_fig_p010_2.png] view at source ↗

Discussion (0). Continue with ORCID to comment.

Forward citations

Cited by 1 Pith paper

Reviewed papers in the Pith corpus that reference this work. Sorted by Pith novelty score. Full citation record

Candidate Resignation Monotonicity in Approval-Based Committee Elections
cs.GT 2026-08 accept novelty 7.0 of 10

Resignation monotonicity is incompatible with justified representation, but the new Maximum Payment Rule and Maximum-Cardinality Affordable Rule recover the PJR+ proportionality guarantee after resignations.

Reference graph

Works this paper leans on

35 extracted references · 34 canonical work pages · cited by 1 Pith paper

[1]

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(2):461--485, 2017

work page 2017
[2]

Broadening the research agenda for computational social choice: Multiple preference profiles and multiple solutions

Niclas Boehmer and Rolf Niedermeier. Broadening the research agenda for computational social choice: Multiple preference profiles and multiple solutions. In Proceedings of the 20th International Conference on Autonomous Agents and Multiagent Systems (AAMAS) , pages 1--5, 2021

work page 2021
[3]

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

work page 2020
[4]

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

work page 2022
[5]

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 (ACM-EC) , page 301, 2023

work page 2023
[6]

Completing priceable committees: Utilitarian and representation guarantees for proportional multiwinner voting

Markus Brill and Jannik Peters. Completing priceable committees: Utilitarian and representation guarantees for proportional multiwinner voting. In Proceedings of the 38th AAAI Conference on Artificial Intelligence (AAAI) , pages 9528--9536, 2024

work page 2024
[7]

Individual representation in approval-based committee voting

Markus Brill, Jonas Israel, Evi Micha, and Jannik Peters. Individual representation in approval-based committee voting. Social Choice and Welfare , 64(1--2):69--96, 2025

work page 2025
[8]

Fair division in a variable setting

Harish Chandramouleeswaran, Prajakta Nimbhorkar, and Nidhi Rathi. Fair division in a variable setting. In Proceedings of the 24th International Conference on Autonomous Agents and Multiagent Systems (AAMAS) , 2025. Forthcoming

work page 2025

Show all 35 references

[9]

Multi-winner reconfiguration

Jiehua Chen, Christian Hatschka, and Sofia Simola. Multi-winner reconfiguration. In Proceedings of the 38th Annual Conference on Neural Information Processing Systems (NeurIPS) , 2024

2024
[10]

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
[11]

Online approval committee elections

Virginie Do, Matthieu Hervouin, J\' e r\^ o me Lang, and Piotr Skowron. Online approval committee elections. In Proceedings of the 31st International Joint Conference on Artificial Intelligence (IJCAI) , pages 251--257, 2022

2022
[12]

Proportional multiwinner voting with dynamic candidate sets

Chris Dong and Jannik Peters. Proportional multiwinner voting with dynamic candidate sets. Working paper. Available at https://pub.dss.in.tum.de/brandt-research/dynamic_multiwinner.pdf, 2024

2024
[13]

Selecting interlacing committees

Chris Dong, Martin Bullinger, Tomasz W a s, Larry Birnbaum, and Edith Elkind. Selecting interlacing committees. In Proceedings of the 24th International Conference on Autonomous Agents and Multiagent Systems (AAMAS) , 2025. Forthcoming

2025
[14]

Structure in dichotomous preferences

Edith Elkind and Martin Lackner. Structure in dichotomous preferences. In Proceedings of the 24th International Joint Conference on Artificial Intelligence (IJCAI) , pages 2019--2025, 2015

2019
[15]

Justifying groups in multiwinner approval voting

Edith Elkind, Piotr Faliszewski, Ayumi Igarashi, Pasin Manurangsi, Ulrike Schmidt-Kraepelin, and Warut Suksompong. Justifying groups in multiwinner approval voting. Theoretical Computer Science , 969:114039, 2023

2023
[16]

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

2024
[17]

Multiwinner voting: A new challenge for social choice theory

Piotr Faliszewski, Piotr Skowron, Arkadii Slinko, and Nimrod Talmon. Multiwinner voting: A new challenge for social choice theory. In Ulle Endriss, editor, Trends in Computational Social Choice , chapter 2, pages 27--47. AI Access, 2017

2017
[18]

o lz, David C. Parkes, Ariel D. Procaccia, Gili Rusak, Itai Shapira, and Manuel W \

Sara Fish, Paul G \"o lz, David C. Parkes, Ariel D. Procaccia, Gili Rusak, Itai Shapira, and Manuel W \"u thrich. Generative social choice. In Proceedings of the 25th ACM Conference on Economics and Computation (ACM-EC) , page 985, 2024

2024
[19]

Kolaitis, Elitza Maneva, and Christos H

Parikshit Gopalan, Phokion G. Kolaitis, Elitza Maneva, and Christos H. Papadimitriou. The connectivity of B oolean satisfiability: Computational and structural dichotomies. SIAM Journal on Computing , 38(6):332--343, 2009

2009
[20]

Reachability of fair allocations via sequential exchanges

Ayumi Igarashi, Naoyuki Kamiyama, Warut Suksompong, and Sheung Man Yuen. Reachability of fair allocations via sequential exchanges. Algorithmica , 86(12):3653--3683, 2024

2024
[21]

Dynamic proportional rankings

Jonas Israel and Markus Brill. Dynamic proportional rankings. Social Choice and Welfare , 64(1--2):221--261, 2025

2025
[22]

Demaine, Nicholas J

Takehiro Ito, Erik D. Demaine, Nicholas J. A. Harvey, Christos H. Papadimitriou, Martha Sideri, Ryuhei Uehara, and Yushi Uno. On the complexity of reconfiguration problems. Theoretical Computer Science , 412(12--14):1054--1065, 2011

2011
[23]

Reforming an envy-free matching

Takehiro Ito, Yuni Iwamasa, Naonori Kakimura, Naoyuki Kamiyama, Yusuke Kobayashi, Yuta Nozaki, Yoshio Okamoto, and Kenta Ozeki. Reforming an envy-free matching. In Proceedings of the 36th AAAI Conference on Artificial Intelligence (AAAI) , pages 5084--5091, 2022

2022
[24]

Finding shortest paths between graph colourings

Matthew Johnson, Dieter Kratsch, Stefan Kratsch, Viresh Patel, and Dani\" e l Paulusma. Finding shortest paths between graph colourings. Algorithmica , 75(2):295--321, 2016

2016
[25]

Proportional fairness in clustering: A social choice perspective

Leon Kellerhals and Jannik Peters. Proportional fairness in clustering: A social choice perspective. In Proceedings of the 38th Annual Conference on Neural Information Processing Systems (NeurIPS) , 2024

2024
[26]

Multi-Winner Voting with Approval Preferences

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

2023
[27]

Introduction to reconfiguration

Naomi Nishimura. Introduction to reconfiguration. Algorithms , 11(4):52:1--52:25, 2018

2018
[28]

On swap-distance geometry of voting rules

Svetlana Obraztsova, Edith Elkind, Piotr Faliszewski, and Arkadii Slinko. On swap-distance geometry of voting rules. In Proceedings of the 12th International Conference on Autonomous Agents and Multiagent Systems (AAMAS) , pages 383--390, 2013

2013
[29]

On swap convexity of voting rules

Svetlana Obraztsova, Edith Elkind, and Piotr Faliszewski. On swap convexity of voting rules. In Proceedings of the 34th AAAI Conference on Artificial Intelligence (AAAI) , pages 1910--1917, 2020

1910
[30]

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 (ACM-EC) , pages 793--794, 2020

2020
[31]

Proportional participatory budgeting with additive utilities

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

2021
[32]

Core-stable committees under restricted domains

Grzegorz Pierczy \'n ski and Piotr Skowron. Core-stable committees under restricted domains. In Proceedings of the 18th International Conference on Web and Internet Economics (WINE) , pages 311--329, 2022

2022
[33]

Walter J. Savitch. Relationships between nondeterministic and deterministic tape complexities. Journal of Computer and System Sciences , 4(2):177--192, 1970

1970
[34]

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
[35]

write newline

" write newline "" before.all 'output.state := FUNCTION fin.entry add.period write newline FUNCTION new.block output.state before.all = 'skip after.block 'output.state := if FUNCTION new.sentence output.state after.block = 'skip output.state before.all = 'skip after.sentence '...

Pith tools

Reviewed August 16, 2026 · model on record in the stance chip above.

[1] [1]

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(2):461--485, 2017

work page 2017

[2] [2]

Broadening the research agenda for computational social choice: Multiple preference profiles and multiple solutions

Niclas Boehmer and Rolf Niedermeier. Broadening the research agenda for computational social choice: Multiple preference profiles and multiple solutions. In Proceedings of the 20th International Conference on Autonomous Agents and Multiagent Systems (AAMAS) , pages 1--5, 2021

work page 2021

[3] [3]

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

work page 2020

[4] [4]

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

work page 2022

[5] [5]

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 (ACM-EC) , page 301, 2023

work page 2023

[6] [6]

Completing priceable committees: Utilitarian and representation guarantees for proportional multiwinner voting

Markus Brill and Jannik Peters. Completing priceable committees: Utilitarian and representation guarantees for proportional multiwinner voting. In Proceedings of the 38th AAAI Conference on Artificial Intelligence (AAAI) , pages 9528--9536, 2024

work page 2024

[7] [7]

Individual representation in approval-based committee voting

Markus Brill, Jonas Israel, Evi Micha, and Jannik Peters. Individual representation in approval-based committee voting. Social Choice and Welfare , 64(1--2):69--96, 2025

work page 2025

[8] [8]

Fair division in a variable setting

Harish Chandramouleeswaran, Prajakta Nimbhorkar, and Nidhi Rathi. Fair division in a variable setting. In Proceedings of the 24th International Conference on Autonomous Agents and Multiagent Systems (AAMAS) , 2025. Forthcoming

work page 2025