---
_id: '12676'
abstract:
- lang: eng
  text: Turn-based stochastic games (aka simple stochastic games) are two-player zero-sum
    games played on directed graphs with probabilistic transitions. The goal of player-max
    is to maximize the probability to reach a target state against the adversarial
    player-min. These games lie in NP ∩ coNP and are among the rare combinatorial
    problems that belong to this complexity class for which the existence of polynomial-time
    algorithm is a major open question. While randomized sub-exponential time algorithm
    exists, all known deterministic algorithms require exponential time in the worst-case.
    An important open question has been whether faster algorithms can be obtained
    parametrized by the treewidth of the game graph. Even deterministic sub-exponential
    time algorithm for constant treewidth turn-based stochastic games has remain elusive.
    In this work our main result is a deterministic algorithm to solve turn-based
    stochastic games that, given a game with n states, treewidth at most t, and the
    bit-complexity of the probabilistic transition function log D, has running time
    O ((tn2 log D)t log n). In particular, our algorithm is quasi-polynomial time
    for games with constant or poly-logarithmic treewidth.
acknowledgement: This research was partially supported by the ERC CoG 863818 (ForM-SMArt)
  grant.
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: Tobias
  full_name: Meggendorfer, Tobias
  id: b21b0c15-30a2-11eb-80dc-f13ca25802e1
  last_name: Meggendorfer
  orcid: 0000-0002-1712-2165
- first_name: Raimundo J
  full_name: Saona Urmeneta, Raimundo J
  id: BD1DF4C4-D767-11E9-B658-BC13E6697425
  last_name: Saona Urmeneta
  orcid: 0000-0001-5103-038X
- first_name: Jakub
  full_name: Svoboda, Jakub
  id: 130759D2-D7DD-11E9-87D2-DE0DE6697425
  last_name: Svoboda
  orcid: 0000-0002-1419-3267
citation:
  ama: 'Chatterjee K, Meggendorfer T, Saona Urmeneta RJ, Svoboda J. Faster algorithm
    for turn-based stochastic games with bounded treewidth. In: <i>Proceedings of
    the 2023 Annual ACM-SIAM Symposium on Discrete Algorithms</i>. Society for Industrial
    and Applied Mathematics; 2023:4590-4605. doi:<a href="https://doi.org/10.1137/1.9781611977554.ch173">10.1137/1.9781611977554.ch173</a>'
  apa: 'Chatterjee, K., Meggendorfer, T., Saona Urmeneta, R. J., &#38; Svoboda, J.
    (2023). Faster algorithm for turn-based stochastic games with bounded treewidth.
    In <i>Proceedings of the 2023 Annual ACM-SIAM Symposium on Discrete Algorithms</i>
    (pp. 4590–4605). Florence, Italy: Society for Industrial and Applied Mathematics.
    <a href="https://doi.org/10.1137/1.9781611977554.ch173">https://doi.org/10.1137/1.9781611977554.ch173</a>'
  chicago: Chatterjee, Krishnendu, Tobias Meggendorfer, Raimundo J Saona Urmeneta,
    and Jakub Svoboda. “Faster Algorithm for Turn-Based Stochastic Games with Bounded
    Treewidth.” In <i>Proceedings of the 2023 Annual ACM-SIAM Symposium on Discrete
    Algorithms</i>, 4590–4605. Society for Industrial and Applied Mathematics, 2023.
    <a href="https://doi.org/10.1137/1.9781611977554.ch173">https://doi.org/10.1137/1.9781611977554.ch173</a>.
  ieee: K. Chatterjee, T. Meggendorfer, R. J. Saona Urmeneta, and J. Svoboda, “Faster
    algorithm for turn-based stochastic games with bounded treewidth,” in <i>Proceedings
    of the 2023 Annual ACM-SIAM Symposium on Discrete Algorithms</i>, Florence, Italy,
    2023, pp. 4590–4605.
  ista: 'Chatterjee K, Meggendorfer T, Saona Urmeneta RJ, Svoboda J. 2023. Faster
    algorithm for turn-based stochastic games with bounded treewidth. Proceedings
    of the 2023 Annual ACM-SIAM Symposium on Discrete Algorithms. SODA: Symposium
    on Discrete Algorithms, 4590–4605.'
  mla: Chatterjee, Krishnendu, et al. “Faster Algorithm for Turn-Based Stochastic
    Games with Bounded Treewidth.” <i>Proceedings of the 2023 Annual ACM-SIAM Symposium
    on Discrete Algorithms</i>, Society for Industrial and Applied Mathematics, 2023,
    pp. 4590–605, doi:<a href="https://doi.org/10.1137/1.9781611977554.ch173">10.1137/1.9781611977554.ch173</a>.
  short: K. Chatterjee, T. Meggendorfer, R.J. Saona Urmeneta, J. Svoboda, in:, Proceedings
    of the 2023 Annual ACM-SIAM Symposium on Discrete Algorithms, Society for Industrial
    and Applied Mathematics, 2023, pp. 4590–4605.
conference:
  end_date: 2023-01-25
  location: Florence, Italy
  name: 'SODA: Symposium on Discrete Algorithms'
  start_date: 2023-01-22
date_created: 2023-02-24T12:20:47Z
date_published: 2023-02-01T00:00:00Z
date_updated: 2025-07-14T09:09:50Z
day: '01'
department:
- _id: GradSch
- _id: KrCh
doi: 10.1137/1.9781611977554.ch173
ec_funded: 1
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://doi.org/10.1137/1.9781611977554.ch173
month: '02'
oa: 1
oa_version: Published Version
page: 4590-4605
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 2023 Annual ACM-SIAM Symposium on Discrete Algorithms
publication_identifier:
  isbn:
  - '9781611977554'
publication_status: published
publisher: Society for Industrial and Applied Mathematics
quality_controlled: '1'
status: public
title: Faster algorithm for turn-based stochastic games with bounded treewidth
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
year: '2023'
...
---
_id: '11447'
abstract:
- lang: eng
  text: Empirical essays of fitness landscapes suggest that they may be rugged, that
    is having multiple fitness peaks. Such fitness landscapes, those that have multiple
    peaks, necessarily have special local structures, called reciprocal sign epistasis
    (Poelwijk et al. in J Theor Biol 272:141–144, 2011). Here, we investigate the
    quantitative relationship between the number of fitness peaks and the number of
    reciprocal sign epistatic interactions. Previously, it has been shown (Poelwijk
    et al. in J Theor Biol 272:141–144, 2011) that pairwise reciprocal sign epistasis
    is a necessary but not sufficient condition for the existence of multiple peaks.
    Applying discrete Morse theory, which to our knowledge has never been used in
    this context, we extend this result by giving the minimal number of reciprocal
    sign epistatic interactions required to create a given number of peaks.
acknowledgement: We are grateful to Herbert Edelsbrunner and Jeferson Zapata for helpful
  discussions. Open access funding provided by Austrian Science Fund (FWF). Partially
  supported by the ERC Consolidator (771209–CharFL) and the FWF Austrian Science Fund
  (I5127-B) grants to FAK.
article_number: '74'
article_processing_charge: Yes (via OA deal)
article_type: original
author:
- first_name: Raimundo J
  full_name: Saona Urmeneta, Raimundo J
  id: BD1DF4C4-D767-11E9-B658-BC13E6697425
  last_name: Saona Urmeneta
  orcid: 0000-0001-5103-038X
- first_name: Fyodor
  full_name: Kondrashov, Fyodor
  id: 44FDEF62-F248-11E8-B48F-1D18A9856A87
  last_name: Kondrashov
  orcid: 0000-0001-8243-4694
- first_name: Kseniia
  full_name: Khudiakova, Kseniia
  id: 4E6DC800-AE37-11E9-AC72-31CAE5697425
  last_name: Khudiakova
  orcid: 0000-0002-6246-1465
citation:
  ama: Saona Urmeneta RJ, Kondrashov F, Khudiakova K. Relation between the number
    of peaks and the number of reciprocal sign epistatic interactions. <i>Bulletin
    of Mathematical Biology</i>. 2022;84(8). doi:<a href="https://doi.org/10.1007/s11538-022-01029-z">10.1007/s11538-022-01029-z</a>
  apa: Saona Urmeneta, R. J., Kondrashov, F., &#38; Khudiakova, K. (2022). Relation
    between the number of peaks and the number of reciprocal sign epistatic interactions.
    <i>Bulletin of Mathematical Biology</i>. Springer Nature. <a href="https://doi.org/10.1007/s11538-022-01029-z">https://doi.org/10.1007/s11538-022-01029-z</a>
  chicago: Saona Urmeneta, Raimundo J, Fyodor Kondrashov, and Kseniia Khudiakova.
    “Relation between the Number of Peaks and the Number of Reciprocal Sign Epistatic
    Interactions.” <i>Bulletin of Mathematical Biology</i>. Springer Nature, 2022.
    <a href="https://doi.org/10.1007/s11538-022-01029-z">https://doi.org/10.1007/s11538-022-01029-z</a>.
  ieee: R. J. Saona Urmeneta, F. Kondrashov, and K. Khudiakova, “Relation between
    the number of peaks and the number of reciprocal sign epistatic interactions,”
    <i>Bulletin of Mathematical Biology</i>, vol. 84, no. 8. Springer Nature, 2022.
  ista: Saona Urmeneta RJ, Kondrashov F, Khudiakova K. 2022. Relation between the
    number of peaks and the number of reciprocal sign epistatic interactions. Bulletin
    of Mathematical Biology. 84(8), 74.
  mla: Saona Urmeneta, Raimundo J., et al. “Relation between the Number of Peaks and
    the Number of Reciprocal Sign Epistatic Interactions.” <i>Bulletin of Mathematical
    Biology</i>, vol. 84, no. 8, 74, Springer Nature, 2022, doi:<a href="https://doi.org/10.1007/s11538-022-01029-z">10.1007/s11538-022-01029-z</a>.
  short: R.J. Saona Urmeneta, F. Kondrashov, K. Khudiakova, Bulletin of Mathematical
    Biology 84 (2022).
date_created: 2022-06-17T16:16:15Z
date_published: 2022-06-17T00:00:00Z
date_updated: 2023-08-03T07:20:53Z
day: '17'
ddc:
- '510'
- '570'
department:
- _id: GradSch
- _id: NiBa
- _id: JaMa
doi: 10.1007/s11538-022-01029-z
ec_funded: 1
external_id:
  isi:
  - '000812509800001'
file:
- access_level: open_access
  checksum: 05a1fe7d10914a00c2bca9b447993a65
  content_type: application/pdf
  creator: dernst
  date_created: 2022-06-20T07:51:32Z
  date_updated: 2022-06-20T07:51:32Z
  file_id: '11455'
  file_name: 2022_BulletinMathBiology_Saona.pdf
  file_size: 463025
  relation: main_file
  success: 1
file_date_updated: 2022-06-20T07:51:32Z
has_accepted_license: '1'
intvolume: '        84'
isi: 1
issue: '8'
keyword:
- Computational Theory and Mathematics
- General Agricultural and Biological Sciences
- Pharmacology
- General Environmental Science
- General Biochemistry
- Genetics and Molecular Biology
- General Mathematics
- Immunology
- General Neuroscience
language:
- iso: eng
license: https://creativecommons.org/licenses/by/4.0/
month: '06'
oa: 1
oa_version: Published Version
project:
- _id: 26580278-B435-11E9-9278-68D0E5697425
  call_identifier: H2020
  grant_number: '771209'
  name: Characterizing the fitness landscape on population and global scales
- _id: c098eddd-5a5b-11eb-8a69-abe27170a68f
  grant_number: I05127
  name: Evolutionary analysis of gene regulation
publication: Bulletin of Mathematical Biology
publication_identifier:
  eissn:
  - 1522-9602
  issn:
  - 0092-8240
publication_status: published
publisher: Springer Nature
quality_controlled: '1'
related_material:
  link:
  - relation: erratum
    url: https://doi.org/10.1007/s11538-022-01118-z
scopus_import: '1'
status: public
title: Relation between the number of peaks and the number of reciprocal sign epistatic
  interactions
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: journal_article
user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8
volume: 84
year: '2022'
...
---
_id: '9311'
abstract:
- lang: eng
  text: 'Partially observable Markov decision processes (POMDPs) are standard models
    for dynamic systems with probabilistic and nondeterministic behaviour in uncertain
    environments. We prove that in POMDPs with long-run average objective, the decision
    maker has approximately optimal strategies with finite memory. This implies notably
    that approximating the long-run value is recursively enumerable, as well as a
    weak continuity property of the value with respect to the transition function. '
acknowledgement: "Partially supported by Austrian Science Fund (FWF) NFN Grant No
  RiSE/SHiNE S11407, by CONICYT Chile through grant PII 20150140, and by ECOS-CONICYT
  through grant C15E03.\r\n"
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: Krishnendu
  full_name: Chatterjee, Krishnendu
  id: 2E5DCA20-F248-11E8-B48F-1D18A9856A87
  last_name: Chatterjee
  orcid: 0000-0002-4561-241X
- first_name: Raimundo J
  full_name: Saona Urmeneta, Raimundo J
  id: BD1DF4C4-D767-11E9-B658-BC13E6697425
  last_name: Saona Urmeneta
  orcid: 0000-0001-5103-038X
- first_name: Bruno
  full_name: Ziliotto, Bruno
  last_name: Ziliotto
citation:
  ama: Chatterjee K, Saona Urmeneta RJ, Ziliotto B. Finite-memory strategies in POMDPs
    with long-run average objectives. <i>Mathematics of Operations Research</i>. 2022;47(1):100-119.
    doi:<a href="https://doi.org/10.1287/moor.2020.1116">10.1287/moor.2020.1116</a>
  apa: Chatterjee, K., Saona Urmeneta, R. J., &#38; Ziliotto, B. (2022). Finite-memory
    strategies in POMDPs with long-run average objectives. <i>Mathematics of Operations
    Research</i>. Institute for Operations Research and the Management Sciences. <a
    href="https://doi.org/10.1287/moor.2020.1116">https://doi.org/10.1287/moor.2020.1116</a>
  chicago: Chatterjee, Krishnendu, Raimundo J Saona Urmeneta, and Bruno Ziliotto.
    “Finite-Memory Strategies in POMDPs with Long-Run Average Objectives.” <i>Mathematics
    of Operations Research</i>. Institute for Operations Research and the Management
    Sciences, 2022. <a href="https://doi.org/10.1287/moor.2020.1116">https://doi.org/10.1287/moor.2020.1116</a>.
  ieee: K. Chatterjee, R. J. Saona Urmeneta, and B. Ziliotto, “Finite-memory strategies
    in POMDPs with long-run average objectives,” <i>Mathematics of Operations Research</i>,
    vol. 47, no. 1. Institute for Operations Research and the Management Sciences,
    pp. 100–119, 2022.
  ista: Chatterjee K, Saona Urmeneta RJ, Ziliotto B. 2022. Finite-memory strategies
    in POMDPs with long-run average objectives. Mathematics of Operations Research.
    47(1), 100–119.
  mla: Chatterjee, Krishnendu, et al. “Finite-Memory Strategies in POMDPs with Long-Run
    Average Objectives.” <i>Mathematics of Operations Research</i>, vol. 47, no. 1,
    Institute for Operations Research and the Management Sciences, 2022, pp. 100–19,
    doi:<a href="https://doi.org/10.1287/moor.2020.1116">10.1287/moor.2020.1116</a>.
  short: K. Chatterjee, R.J. Saona Urmeneta, B. Ziliotto, Mathematics of Operations
    Research 47 (2022) 100–119.
date_created: 2021-04-08T09:33:31Z
date_published: 2022-02-01T00:00:00Z
date_updated: 2023-09-05T13:16:11Z
day: '01'
department:
- _id: GradSch
- _id: KrCh
doi: 10.1287/moor.2020.1116
external_id:
  arxiv:
  - '1904.13360'
  isi:
  - '000731918100001'
intvolume: '        47'
isi: 1
issue: '1'
keyword:
- Management Science and Operations Research
- General Mathematics
- Computer Science Applications
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://arxiv.org/abs/1904.13360
month: '02'
oa: 1
oa_version: Preprint
page: 100-119
project:
- _id: 25863FF4-B435-11E9-9278-68D0E5697425
  call_identifier: FWF
  grant_number: S11407
  name: Game Theory
publication: Mathematics of Operations Research
publication_identifier:
  eissn:
  - 1526-5471
  issn:
  - 0364-765X
publication_status: published
publisher: Institute for Operations Research and the Management Sciences
quality_controlled: '1'
scopus_import: '1'
status: public
title: Finite-memory strategies in POMDPs with long-run average objectives
type: journal_article
user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1
volume: 47
year: '2022'
...
---
_id: '12677'
abstract:
- lang: eng
  text: "In modern sample-driven Prophet Inequality, an adversary chooses a sequence
    of n items with values v1,v2,…,vn to be presented to a decision maker (DM). The
    process follows in two phases. In the first phase (sampling phase), some items,
    possibly selected at random, are revealed to the DM, but she can never accept
    them. In the second phase, the DM is presented with the other items in a random
    order and online fashion. For each item, she must make an irrevocable decision
    to either accept the item and stop the process or reject the item forever and
    proceed to the next item. The goal of the DM is to maximize the expected value
    as compared to a Prophet (or offline algorithm) that has access to all information.
    In this setting, the sampling phase has no cost and is not part of the optimization
    process. However, in many scenarios, the samples are obtained as part of the decision-making
    process.\r\nWe model this aspect as a two-phase Prophet Inequality where an adversary
    chooses a sequence of 2n items with values v1,v2,…,v2n and the items are randomly
    ordered. Finally, there are two phases of the Prophet Inequality problem with
    the first n-items and the rest of the items, respectively. We show that some basic
    algorithms achieve a ratio of at most 0.450. We present an algorithm that achieves
    a ratio of at least 0.495. Finally, we show that for every algorithm the ratio
    it can achieve is at most 0.502. Hence our algorithm is near-optimal."
acknowledgement: This research was partially supported by the ERC CoG 863818 (ForM-SMArt)
  grant.
article_number: '2209.14368'
article_processing_charge: No
arxiv: 1
author:
- first_name: Krishnendu
  full_name: Chatterjee, Krishnendu
  id: 2E5DCA20-F248-11E8-B48F-1D18A9856A87
  last_name: Chatterjee
  orcid: 0000-0002-4561-241X
- first_name: Mona
  full_name: Mohammadi, Mona
  id: 4363614d-b686-11ed-a7d5-ac9e4a24bc2e
  last_name: Mohammadi
- first_name: Raimundo J
  full_name: Saona Urmeneta, Raimundo J
  id: BD1DF4C4-D767-11E9-B658-BC13E6697425
  last_name: Saona Urmeneta
  orcid: 0000-0001-5103-038X
citation:
  ama: Chatterjee K, Mohammadi M, Saona Urmeneta RJ. Repeated prophet inequality with
    near-optimal bounds. <i>arXiv</i>. doi:<a href="https://doi.org/10.48550/ARXIV.2209.14368">10.48550/ARXIV.2209.14368</a>
  apa: Chatterjee, K., Mohammadi, M., &#38; Saona Urmeneta, R. J. (n.d.). Repeated
    prophet inequality with near-optimal bounds. <i>arXiv</i>. <a href="https://doi.org/10.48550/ARXIV.2209.14368">https://doi.org/10.48550/ARXIV.2209.14368</a>
  chicago: Chatterjee, Krishnendu, Mona Mohammadi, and Raimundo J Saona Urmeneta.
    “Repeated Prophet Inequality with Near-Optimal Bounds.” <i>ArXiv</i>, n.d. <a
    href="https://doi.org/10.48550/ARXIV.2209.14368">https://doi.org/10.48550/ARXIV.2209.14368</a>.
  ieee: K. Chatterjee, M. Mohammadi, and R. J. Saona Urmeneta, “Repeated prophet inequality
    with near-optimal bounds,” <i>arXiv</i>. .
  ista: Chatterjee K, Mohammadi M, Saona Urmeneta RJ. Repeated prophet inequality
    with near-optimal bounds. arXiv, 2209.14368.
  mla: Chatterjee, Krishnendu, et al. “Repeated Prophet Inequality with Near-Optimal
    Bounds.” <i>ArXiv</i>, 2209.14368, doi:<a href="https://doi.org/10.48550/ARXIV.2209.14368">10.48550/ARXIV.2209.14368</a>.
  short: K. Chatterjee, M. Mohammadi, R.J. Saona Urmeneta, ArXiv (n.d.).
date_created: 2023-02-24T12:21:40Z
date_published: 2022-09-28T00:00:00Z
date_updated: 2025-07-14T09:09:51Z
day: '28'
department:
- _id: GradSch
- _id: KrCh
doi: 10.48550/ARXIV.2209.14368
ec_funded: 1
external_id:
  arxiv:
  - '2209.14368'
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: ' https://doi.org/10.48550/arXiv.2209.14368'
month: '09'
oa: 1
oa_version: Preprint
project:
- _id: 0599E47C-7A3F-11EA-A408-12923DDC885E
  call_identifier: H2020
  grant_number: '863818'
  name: 'Formal Methods for Stochastic Models: Algorithms and Applications'
publication: arXiv
publication_status: submitted
status: public
title: Repeated prophet inequality with near-optimal bounds
type: preprint
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
year: '2022'
...
