---
OA_place: publisher
OA_type: hybrid
_id: '20052'
abstract:
- lang: eng
  text: "This paper revisits a fundamental distributed computing problem in the population
    protocol model. Provided n agents each starting with an input color in [k], the
    relative majority problem asks to find the predominant color. In the population
    protocol model, at each time step, a scheduler selects two agents that first learn
    each other's states and then update their states based on what they learned.\r\nWe
    present the Circles protocol that solves the relative majority problem with k3
    states. It is always-correct under weakly fair scheduling. Not only does it improve
    upon the best known upper bound of O(k7), but it also shows a strikingly simpler
    design inspired by energy minimization in chemical settings."
acknowledgement: 'This project has received funding from the European Research Council
  (ERC) under the European Union’s Horizon 2020 research and innovation programme
  (MoDynStruct, No. 101019564) and the Austrian Science Fund (FWF) grant DOI 10.55776/I5982,
  and grant DOI 10.55776/P33775 with additional funding from the netidee SCIENCE Stiftung,
  2020–2024 and the German Research Foundation (DFG), grant 470029389 (FlexNets). '
article_processing_charge: No
author:
- first_name: Tom-Lukas
  full_name: Breitkopf, Tom-Lukas
  last_name: Breitkopf
- first_name: Julien
  full_name: Dallot, Julien
  last_name: Dallot
- first_name: Antoine
  full_name: El-Hayek, Antoine
  id: 888a098e-fcac-11ee-aff7-d347be57b725
  last_name: El-Hayek
  orcid: 0000-0003-4268-7368
- first_name: Stefan
  full_name: Schmid, Stefan
  last_name: Schmid
citation:
  ama: 'Breitkopf T-L, Dallot J, El-Hayek A, Schmid S. Brief announcement: Minimizing
    energy solves relative majority with a cubic number of states in population protocols.
    In: <i>Proceedings of the ACM Symposium on Principles of Distributed Computing</i>.
    Association for Computing Machinery; 2025:549-552. doi:<a href="https://doi.org/10.1145/3732772.3733512">10.1145/3732772.3733512</a>'
  apa: 'Breitkopf, T.-L., Dallot, J., El-Hayek, A., &#38; Schmid, S. (2025). Brief
    announcement: Minimizing energy solves relative majority with a cubic number of
    states in population protocols. In <i>Proceedings of the ACM Symposium on Principles
    of Distributed Computing</i> (pp. 549–552). Huatulco, Mexico: Association for
    Computing Machinery. <a href="https://doi.org/10.1145/3732772.3733512">https://doi.org/10.1145/3732772.3733512</a>'
  chicago: 'Breitkopf, Tom-Lukas, Julien Dallot, Antoine El-Hayek, and Stefan Schmid.
    “Brief Announcement: Minimizing Energy Solves Relative Majority with a Cubic Number
    of States in Population Protocols.” In <i>Proceedings of the ACM Symposium on
    Principles of Distributed Computing</i>, 549–52. Association for Computing Machinery,
    2025. <a href="https://doi.org/10.1145/3732772.3733512">https://doi.org/10.1145/3732772.3733512</a>.'
  ieee: 'T.-L. Breitkopf, J. Dallot, A. El-Hayek, and S. Schmid, “Brief announcement:
    Minimizing energy solves relative majority with a cubic number of states in population
    protocols,” in <i>Proceedings of the ACM Symposium on Principles of Distributed
    Computing</i>, Huatulco, Mexico, 2025, pp. 549–552.'
  ista: 'Breitkopf T-L, Dallot J, El-Hayek A, Schmid S. 2025. Brief announcement:
    Minimizing energy solves relative majority with a cubic number of states in population
    protocols. Proceedings of the ACM Symposium on Principles of Distributed Computing.
    PODC: Symposium on Principles of Distributed Computing, 549–552.'
  mla: 'Breitkopf, Tom-Lukas, et al. “Brief Announcement: Minimizing Energy Solves
    Relative Majority with a Cubic Number of States in Population Protocols.” <i>Proceedings
    of the ACM Symposium on Principles of Distributed Computing</i>, Association for
    Computing Machinery, 2025, pp. 549–52, doi:<a href="https://doi.org/10.1145/3732772.3733512">10.1145/3732772.3733512</a>.'
  short: T.-L. Breitkopf, J. Dallot, A. El-Hayek, S. Schmid, in:, Proceedings of the
    ACM Symposium on Principles of Distributed Computing, Association for Computing
    Machinery, 2025, pp. 549–552.
conference:
  end_date: 2025-06-20
  location: Huatulco, Mexico
  name: 'PODC: Symposium on Principles of Distributed Computing'
  start_date: 2025-06-16
corr_author: '1'
date_created: 2025-07-21T08:17:04Z
date_published: 2025-06-13T00:00:00Z
date_updated: 2026-02-16T11:46:37Z
day: '13'
ddc:
- '000'
department:
- _id: MoHe
doi: 10.1145/3732772.3733512
ec_funded: 1
external_id:
  isi:
  - '001525534800069'
file:
- access_level: open_access
  checksum: e99679ffb28877b7cea4d54860302790
  content_type: application/pdf
  creator: dernst
  date_created: 2025-08-05T07:32:01Z
  date_updated: 2025-08-05T07:32:01Z
  file_id: '20123'
  file_name: 2025_PODC_Breitkopf.pdf
  file_size: 549706
  relation: main_file
  success: 1
file_date_updated: 2025-08-05T07:32:01Z
fulldoi: https://doi.org/10.1145/3732772.3733512
has_accepted_license: '1'
isi: 1
language:
- iso: eng
month: '06'
oa: 1
oa_version: Published Version
page: 549-552
project:
- _id: bd9ca328-d553-11ed-ba76-dc4f890cfe62
  call_identifier: H2020
  grant_number: '101019564'
  name: The design and evaluation of modern fully dynamic data structures
- _id: bda196b2-d553-11ed-ba76-8e8ee6c21103
  grant_number: I05982
  name: Static and Dynamic Hierarchical Graph Decompositions
- _id: bd9e3a2e-d553-11ed-ba76-8aa684ce17fe
  grant_number: P33775
  name: Fast Algorithms for a Reactive Network Layer
publication: Proceedings of the ACM Symposium on Principles of Distributed Computing
publication_identifier:
  isbn:
  - '9798400718854'
publication_status: published
publisher: Association for Computing Machinery
quality_controlled: '1'
status: public
title: 'Brief announcement: Minimizing energy solves relative majority with a cubic
  number of states in population protocols'
tmp:
  image: /images/cc_by.png
  legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
  name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
  short: CC BY (4.0)
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
year: '2025'
...
---
OA_place: publisher
OA_type: hybrid
_id: '20053'
abstract:
- lang: eng
  text: "Liquid democracy is a transitive vote delegation mechanism over voting graphs.
    It enables each voter to delegate their vote(s) to another better-informed voter,
    with the goal of collectively making a better decision. The question of whether
    liquid democracy outperforms direct voting has been previously studied in the
    context of local delegation mechanisms (where voters can only delegate to someone
    in their neighbourhood) and binary decision problems. It has previously been shown
    that it is impossible for local delegation mechanisms to outperform direct voting
    in general graphs. This raises the question: for which classes of graphs do local
    delegation mechanisms yield good results?\r\nIn this work, we analyse (1) properties
    of specific graphs and (2) properties of local delegation mechanisms on these
    graphs, determining where local delegation actually outperforms direct voting.
    We show that a critical graph property enabling liquid democracy is that the voting
    outcome of local delegation mechanisms preserves a sufficient amount of variance,
    thereby avoiding situations where delegation falls behind direct voting1. These
    insights allow us to prove our main results, namely that there exist local delegation
    mechanisms that perform no worse and in fact quantitatively better than direct
    voting in natural graph topologies like complete, random d-regular, and bounded
    degree graphs, lending a more nuanced perspective to previous impossibility results."
acknowledgement: This work was partially supported by MOE-T2EP20122-0014 (DataDriven
  Distributed Algorithms), German Research Foundation (DFG) project ReNO (SPP 2378)
  from 2023-2027, ERC CoG 863818 (ForMSMArt) and Austrian Science Fund (FWF) 10.55776/COE12.
article_processing_charge: No
author:
- first_name: Krishnendu
  full_name: Chatterjee, Krishnendu
  id: 2E5DCA20-F248-11E8-B48F-1D18A9856A87
  last_name: Chatterjee
  orcid: 0000-0002-4561-241X
- first_name: Seth
  full_name: Gilbert, Seth
  last_name: Gilbert
- first_name: Stefan
  full_name: Schmid, Stefan
  last_name: Schmid
- first_name: Jakub
  full_name: Svoboda, Jakub
  id: 130759D2-D7DD-11E9-87D2-DE0DE6697425
  last_name: Svoboda
  orcid: 0000-0002-1419-3267
- first_name: Michelle X
  full_name: Yeo, Michelle X
  id: 2D82B818-F248-11E8-B48F-1D18A9856A87
  last_name: Yeo
  orcid: 0009-0001-3676-4809
citation:
  ama: 'Chatterjee K, Gilbert S, Schmid S, Svoboda J, Yeo MX. When is liquid democracy
    possible?: On the manipulation of variance. In: <i>Proceedings of the ACM Symposium
    on Principles of Distributed Computing</i>. Association for Computing Machinery;
    2025:241-251. doi:<a href="https://doi.org/10.1145/3732772.3733544">10.1145/3732772.3733544</a>'
  apa: 'Chatterjee, K., Gilbert, S., Schmid, S., Svoboda, J., &#38; Yeo, M. X. (2025).
    When is liquid democracy possible?: On the manipulation of variance. In <i>Proceedings
    of the ACM Symposium on Principles of Distributed Computing</i> (pp. 241–251).
    Huatulco, Mexico: Association for Computing Machinery. <a href="https://doi.org/10.1145/3732772.3733544">https://doi.org/10.1145/3732772.3733544</a>'
  chicago: 'Chatterjee, Krishnendu, Seth Gilbert, Stefan Schmid, Jakub Svoboda, and
    Michelle X Yeo. “When Is Liquid Democracy Possible?: On the Manipulation of Variance.”
    In <i>Proceedings of the ACM Symposium on Principles of Distributed Computing</i>,
    241–51. Association for Computing Machinery, 2025. <a href="https://doi.org/10.1145/3732772.3733544">https://doi.org/10.1145/3732772.3733544</a>.'
  ieee: 'K. Chatterjee, S. Gilbert, S. Schmid, J. Svoboda, and M. X. Yeo, “When is
    liquid democracy possible?: On the manipulation of variance,” in <i>Proceedings
    of the ACM Symposium on Principles of Distributed Computing</i>, Huatulco, Mexico,
    2025, pp. 241–251.'
  ista: 'Chatterjee K, Gilbert S, Schmid S, Svoboda J, Yeo MX. 2025. When is liquid
    democracy possible?: On the manipulation of variance. Proceedings of the ACM Symposium
    on Principles of Distributed Computing. PODC: Symposium on Principles of Distributed
    Computing, 241–251.'
  mla: 'Chatterjee, Krishnendu, et al. “When Is Liquid Democracy Possible?: On the
    Manipulation of Variance.” <i>Proceedings of the ACM Symposium on Principles of
    Distributed Computing</i>, Association for Computing Machinery, 2025, pp. 241–51,
    doi:<a href="https://doi.org/10.1145/3732772.3733544">10.1145/3732772.3733544</a>.'
  short: K. Chatterjee, S. Gilbert, S. Schmid, J. Svoboda, M.X. Yeo, in:, Proceedings
    of the ACM Symposium on Principles of Distributed Computing, Association for Computing
    Machinery, 2025, pp. 241–251.
conference:
  end_date: 2025-06-20
  location: Huatulco, Mexico
  name: 'PODC: Symposium on Principles of Distributed Computing'
  start_date: 2025-06-16
corr_author: '1'
date_created: 2025-07-21T08:18:26Z
date_published: 2025-06-13T00:00:00Z
date_updated: 2026-02-16T11:46:51Z
day: '13'
ddc:
- '000'
department:
- _id: KrCh
- _id: KrPi
doi: 10.1145/3732772.3733544
ec_funded: 1
external_id:
  isi:
  - '001525534800030'
file:
- access_level: open_access
  checksum: cd628fe54d96e9fc6cc789bb8145422b
  content_type: application/pdf
  creator: dernst
  date_created: 2025-08-05T07:15:31Z
  date_updated: 2025-08-05T07:15:31Z
  file_id: '20122'
  file_name: 2025_PODC_Chatterjee.pdf
  file_size: 783297
  relation: main_file
  success: 1
file_date_updated: 2025-08-05T07:15:31Z
fulldoi: https://doi.org/10.1145/3732772.3733544
has_accepted_license: '1'
isi: 1
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://eprint.iacr.org/2025/745
month: '06'
oa: 1
oa_version: Published Version
page: 241-251
project:
- _id: 0599E47C-7A3F-11EA-A408-12923DDC885E
  call_identifier: H2020
  grant_number: '863818'
  name: 'Formal Methods for Stochastic Models: Algorithms and Applications'
publication: Proceedings of the ACM Symposium on Principles of Distributed Computing
publication_identifier:
  isbn:
  - '9798400718854'
publication_status: published
publisher: Association for Computing Machinery
quality_controlled: '1'
status: public
title: 'When is liquid democracy possible?: On the manipulation of variance'
tmp:
  image: /images/cc_by.png
  legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
  name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
  short: CC BY (4.0)
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
year: '2025'
...
