---
_id: '14244'
abstract:
- lang: eng
  text: "In this paper, we determine the motivic class — in particular, the weight
    polynomial and conjecturally the Poincaré polynomial — of the open de Rham space,
    defined and studied by Boalch, of certain moduli spaces of irregular meromorphic
    connections on the trivial rank \r\n bundle on P1. The computation is by motivic
    Fourier transform. We show that the result satisfies the purity conjecture, that
    is, it agrees with the pure part of the conjectured mixed Hodge polynomial of
    the corresponding wild character variety. We also identify the open de Rham spaces
    with quiver varieties with multiplicities of Yamakawa and Geiss–Leclerc–Schröer.
    We finish with constructing natural complete hyperkähler metrics on them, which
    in the four-dimensional cases are expected to be of type ALF."
acknowledgement: We would like to thank Gergely Bérczy, Roger Bielawski, Philip Boalch,
  Sergey Cherkis, Andrew Dancer, Brent Doran, Eloïse Hamilton, Frances Kirwan, Bernard
  Leclerc, Emmanuel Letellier, Alessia Mandini, Maxence Mayrand, András Némethi, Szilárd
  Szabó, and Daisuke Yamakawa for discussions related to the paper. We especially
  thank the referee for an extensive list of very careful comments. At various stages
  of this project, the authors were supported by the Advanced Grant “Arithmetic and
  physics of Higgs moduli spaces” no. 320593 of the European Research Council, by
  grant no. 153627 and NCCR SwissMAP, both funded by the Swiss National Science Foundation
  as well as by EPF Lausanne and IST Austria. In the final stages of this project,
  MLW was supported by SFB/TR 45 “Periods, moduli and arithmetic of algebraic varieties,”
  subproject M08-10 “Moduli of vector bundles on higher-dimensional varieties.” DW
  was also supported by the Fondation Sciences Mathématiques de Paris, as well as
  public grants overseen by the Agence national de la recherche (ANR) of France as
  part of the Investissements d'avenir program, under reference numbers ANR-10-LABX-0098
  and ANR-15-CE40-0008 (Défigéo).
article_processing_charge: Yes (via OA deal)
article_type: original
arxiv: 1
author:
- first_name: Tamás
  full_name: Hausel, Tamás
  id: 4A0666D8-F248-11E8-B48F-1D18A9856A87
  last_name: Hausel
- first_name: Michael Lennox
  full_name: Wong, Michael Lennox
  last_name: Wong
- first_name: Dimitri
  full_name: Wyss, Dimitri
  last_name: Wyss
citation:
  ama: Hausel T, Wong ML, Wyss D. Arithmetic and metric aspects of open de Rham spaces.
    <i>Proceedings of the London Mathematical Society</i>. 2023;127(4):958-1027. doi:<a
    href="https://doi.org/10.1112/plms.12555">10.1112/plms.12555</a>
  apa: Hausel, T., Wong, M. L., &#38; Wyss, D. (2023). Arithmetic and metric aspects
    of open de Rham spaces. <i>Proceedings of the London Mathematical Society</i>.
    Wiley. <a href="https://doi.org/10.1112/plms.12555">https://doi.org/10.1112/plms.12555</a>
  chicago: Hausel, Tamás, Michael Lennox Wong, and Dimitri Wyss. “Arithmetic and Metric
    Aspects of Open de Rham Spaces.” <i>Proceedings of the London Mathematical Society</i>.
    Wiley, 2023. <a href="https://doi.org/10.1112/plms.12555">https://doi.org/10.1112/plms.12555</a>.
  ieee: T. Hausel, M. L. Wong, and D. Wyss, “Arithmetic and metric aspects of open
    de Rham spaces,” <i>Proceedings of the London Mathematical Society</i>, vol. 127,
    no. 4. Wiley, pp. 958–1027, 2023.
  ista: Hausel T, Wong ML, Wyss D. 2023. Arithmetic and metric aspects of open de
    Rham spaces. Proceedings of the London Mathematical Society. 127(4), 958–1027.
  mla: Hausel, Tamás, et al. “Arithmetic and Metric Aspects of Open de Rham Spaces.”
    <i>Proceedings of the London Mathematical Society</i>, vol. 127, no. 4, Wiley,
    2023, pp. 958–1027, doi:<a href="https://doi.org/10.1112/plms.12555">10.1112/plms.12555</a>.
  short: T. Hausel, M.L. Wong, D. Wyss, Proceedings of the London Mathematical Society
    127 (2023) 958–1027.
date_created: 2023-08-27T22:01:18Z
date_published: 2023-10-01T00:00:00Z
date_updated: 2024-01-30T12:56:10Z
day: '01'
ddc:
- '510'
department:
- _id: TaHa
doi: 10.1112/plms.12555
ec_funded: 1
external_id:
  arxiv:
  - '1807.04057'
  isi:
  - '001049312700001'
file:
- access_level: open_access
  checksum: 2af4d2d6a8ae42f7d3fba0188e79ae82
  content_type: application/pdf
  creator: dernst
  date_created: 2024-01-30T12:56:00Z
  date_updated: 2024-01-30T12:56:00Z
  file_id: '14910'
  file_name: 2023_ProcLondonMathSoc_Hausel.pdf
  file_size: 651335
  relation: main_file
  success: 1
file_date_updated: 2024-01-30T12:56:00Z
has_accepted_license: '1'
intvolume: '       127'
isi: 1
issue: '4'
language:
- iso: eng
month: '10'
oa: 1
oa_version: Published Version
page: 958-1027
project:
- _id: 25E549F4-B435-11E9-9278-68D0E5697425
  call_identifier: FP7
  grant_number: '320593'
  name: Arithmetic and physics of Higgs moduli spaces
- _id: 25E6C798-B435-11E9-9278-68D0E5697425
  grant_number: '153627'
  name: Arithmetic quantization of character and quiver varities
publication: Proceedings of the London Mathematical Society
publication_identifier:
  eissn:
  - 1460-244X
  issn:
  - 0024-6115
publication_status: published
publisher: Wiley
quality_controlled: '1'
scopus_import: '1'
status: public
title: Arithmetic and metric aspects of open de Rham spaces
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: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 127
year: '2023'
...
---
_id: '9581'
abstract:
- lang: eng
  text: "We show that for any  \U0001D45B  divisible by 3, almost all order-  \U0001D45B
    \ Steiner triple systems have a perfect matching (also known as a parallel class
    or resolution class). In fact, we prove a general upper bound on the number of
    perfect matchings in a Steiner triple system and show that almost all Steiner
    triple systems essentially attain this maximum. We accomplish this via a general
    theorem comparing a uniformly random Steiner triple system to the outcome of the
    triangle removal process, which we hope will be useful for other problems. Our
    methods can also be adapted to other types of designs; for example, we sketch
    a proof of the theorem that almost all Latin squares have transversals."
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: Matthew Alan
  full_name: Kwan, Matthew Alan
  id: 5fca0887-a1db-11eb-95d1-ca9d5e0453b3
  last_name: Kwan
  orcid: 0000-0002-4003-7567
citation:
  ama: Kwan MA. Almost all Steiner triple systems have perfect matchings. <i>Proceedings
    of the London Mathematical Society</i>. 2020;121(6):1468-1495. doi:<a href="https://doi.org/10.1112/plms.12373">10.1112/plms.12373</a>
  apa: Kwan, M. A. (2020). Almost all Steiner triple systems have perfect matchings.
    <i>Proceedings of the London Mathematical Society</i>. Wiley. <a href="https://doi.org/10.1112/plms.12373">https://doi.org/10.1112/plms.12373</a>
  chicago: Kwan, Matthew Alan. “Almost All Steiner Triple Systems Have Perfect Matchings.”
    <i>Proceedings of the London Mathematical Society</i>. Wiley, 2020. <a href="https://doi.org/10.1112/plms.12373">https://doi.org/10.1112/plms.12373</a>.
  ieee: M. A. Kwan, “Almost all Steiner triple systems have perfect matchings,” <i>Proceedings
    of the London Mathematical Society</i>, vol. 121, no. 6. Wiley, pp. 1468–1495,
    2020.
  ista: Kwan MA. 2020. Almost all Steiner triple systems have perfect matchings. Proceedings
    of the London Mathematical Society. 121(6), 1468–1495.
  mla: Kwan, Matthew Alan. “Almost All Steiner Triple Systems Have Perfect Matchings.”
    <i>Proceedings of the London Mathematical Society</i>, vol. 121, no. 6, Wiley,
    2020, pp. 1468–95, doi:<a href="https://doi.org/10.1112/plms.12373">10.1112/plms.12373</a>.
  short: M.A. Kwan, Proceedings of the London Mathematical Society 121 (2020) 1468–1495.
date_created: 2021-06-22T06:35:16Z
date_published: 2020-12-01T00:00:00Z
date_updated: 2023-02-23T14:01:43Z
day: '01'
doi: 10.1112/plms.12373
extern: '1'
external_id:
  arxiv:
  - '1611.02246'
intvolume: '       121'
issue: '6'
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://arxiv.org/abs/1611.02246
month: '12'
oa: 1
oa_version: Preprint
page: 1468-1495
publication: Proceedings of the London Mathematical Society
publication_identifier:
  eissn:
  - 1460-244X
  issn:
  - 0024-6115
publication_status: published
publisher: Wiley
quality_controlled: '1'
scopus_import: '1'
status: public
title: Almost all Steiner triple systems have perfect matchings
type: journal_article
user_id: 6785fbc1-c503-11eb-8a32-93094b40e1cf
volume: 121
year: '2020'
...
---
_id: '5999'
abstract:
- lang: eng
  text: "We introduce for each quiver Q and each algebraic oriented cohomology theory
    A, the cohomological Hall algebra (CoHA) of Q, as the A-homology of the moduli
    of representations of the preprojective algebra of Q. This generalizes the K-theoretic
    Hall algebra of commuting varieties defined by Schiffmann-Vasserot. When A is
    the Morava K-theory, we show evidence that this algebra is a candidate for Lusztig's
    reformulated conjecture on modular representations of algebraic groups.\r\nWe
    construct an action of the preprojective CoHA on the A-homology of Nakajima quiver
    varieties. We compare this with the action of the Borel subalgebra of Yangian
    when A is the intersection theory. We also give a shuffle algebra description
    of this CoHA in terms of the underlying formal group law of A. As applications,
    we obtain a shuffle description of the Yangian. "
article_processing_charge: No
arxiv: 1
author:
- first_name: Yaping
  full_name: Yang, Yaping
  last_name: Yang
- first_name: Gufang
  full_name: Zhao, Gufang
  id: 2BC2AC5E-F248-11E8-B48F-1D18A9856A87
  last_name: Zhao
citation:
  ama: Yang Y, Zhao G. The cohomological Hall algebra of a preprojective algebra.
    <i>Proceedings of the London Mathematical Society</i>. 2018;116(5):1029-1074.
    doi:<a href="https://doi.org/10.1112/plms.12111">10.1112/plms.12111</a>
  apa: Yang, Y., &#38; Zhao, G. (2018). The cohomological Hall algebra of a preprojective
    algebra. <i>Proceedings of the London Mathematical Society</i>. Oxford University
    Press. <a href="https://doi.org/10.1112/plms.12111">https://doi.org/10.1112/plms.12111</a>
  chicago: Yang, Yaping, and Gufang Zhao. “The Cohomological Hall Algebra of a Preprojective
    Algebra.” <i>Proceedings of the London Mathematical Society</i>. Oxford University
    Press, 2018. <a href="https://doi.org/10.1112/plms.12111">https://doi.org/10.1112/plms.12111</a>.
  ieee: Y. Yang and G. Zhao, “The cohomological Hall algebra of a preprojective algebra,”
    <i>Proceedings of the London Mathematical Society</i>, vol. 116, no. 5. Oxford
    University Press, pp. 1029–1074, 2018.
  ista: Yang Y, Zhao G. 2018. The cohomological Hall algebra of a preprojective algebra.
    Proceedings of the London Mathematical Society. 116(5), 1029–1074.
  mla: Yang, Yaping, and Gufang Zhao. “The Cohomological Hall Algebra of a Preprojective
    Algebra.” <i>Proceedings of the London Mathematical Society</i>, vol. 116, no.
    5, Oxford University Press, 2018, pp. 1029–74, doi:<a href="https://doi.org/10.1112/plms.12111">10.1112/plms.12111</a>.
  short: Y. Yang, G. Zhao, Proceedings of the London Mathematical Society 116 (2018)
    1029–1074.
date_created: 2019-02-14T13:14:22Z
date_published: 2018-05-01T00:00:00Z
date_updated: 2023-09-19T14:37:19Z
day: '01'
department:
- _id: TaHa
doi: 10.1112/plms.12111
external_id:
  arxiv:
  - '1407.7994'
  isi:
  - '000431506400001'
intvolume: '       116'
isi: 1
issue: '5'
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://arxiv.org/abs/1407.7994
month: '05'
oa: 1
oa_version: Preprint
page: 1029-1074
publication: Proceedings of the London Mathematical Society
publication_identifier:
  issn:
  - 0024-6115
publication_status: published
publisher: Oxford University Press
quality_controlled: '1'
scopus_import: '1'
status: public
title: The cohomological Hall algebra of a preprojective algebra
type: journal_article
user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1
volume: 116
year: '2018'
...
---
_id: '270'
abstract:
- lang: eng
  text: Given a symmetric variety Y defined over Q and a non-zero polynomial with
    integer coefficients, we use techniques from homogeneous dynamics to establish
    conditions under which the polynomial can be made r-free for a Zariski dense set
    of integral points on Y . We also establish an asymptotic counting formula for
    this set. In the special case that Y is a quadric hypersurface, we give explicit
    bounds on the size of r by combining the argument with a uniform upper bound for
    the density of integral points on general affine quadrics defined over Q.
acknowledgement: While working on this paper the authors were supported by ERC grants
  306457 and 239606, respectively.
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: Timothy D
  full_name: Browning, Timothy D
  id: 35827D50-F248-11E8-B48F-1D18A9856A87
  last_name: Browning
  orcid: 0000-0002-8314-0177
- first_name: Alexander
  full_name: Gorodnik, Alexander
  last_name: Gorodnik
citation:
  ama: Browning TD, Gorodnik A. Power-free values of polynomials on symmetric varieties.
    <i>Proceedings of the London Mathematical Society</i>. 2017;114(6):1044-1080.
    doi:<a href="https://doi.org/10.1112/plms.12030">10.1112/plms.12030</a>
  apa: Browning, T. D., &#38; Gorodnik, A. (2017). Power-free values of polynomials
    on symmetric varieties. <i>Proceedings of the London Mathematical Society</i>.
    Wiley. <a href="https://doi.org/10.1112/plms.12030">https://doi.org/10.1112/plms.12030</a>
  chicago: Browning, Timothy D, and Alexander Gorodnik. “Power-Free Values of Polynomials
    on Symmetric Varieties.” <i>Proceedings of the London Mathematical Society</i>.
    Wiley, 2017. <a href="https://doi.org/10.1112/plms.12030">https://doi.org/10.1112/plms.12030</a>.
  ieee: T. D. Browning and A. Gorodnik, “Power-free values of polynomials on symmetric
    varieties,” <i>Proceedings of the London Mathematical Society</i>, vol. 114, no.
    6. Wiley, pp. 1044–1080, 2017.
  ista: Browning TD, Gorodnik A. 2017. Power-free values of polynomials on symmetric
    varieties. Proceedings of the London Mathematical Society. 114(6), 1044–1080.
  mla: Browning, Timothy D., and Alexander Gorodnik. “Power-Free Values of Polynomials
    on Symmetric Varieties.” <i>Proceedings of the London Mathematical Society</i>,
    vol. 114, no. 6, Wiley, 2017, pp. 1044–80, doi:<a href="https://doi.org/10.1112/plms.12030">10.1112/plms.12030</a>.
  short: T.D. Browning, A. Gorodnik, Proceedings of the London Mathematical Society
    114 (2017) 1044–1080.
date_created: 2018-12-11T11:45:32Z
date_published: 2017-06-01T00:00:00Z
date_updated: 2024-03-05T11:58:25Z
day: '01'
doi: 10.1112/plms.12030
extern: '1'
external_id:
  arxiv:
  - '1606.06342'
intvolume: '       114'
issue: '6'
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://arxiv.org/abs/1606.06342
month: '06'
oa: 1
oa_version: Preprint
page: 1044 - 1080
publication: Proceedings of the London Mathematical Society
publication_identifier:
  issn:
  - 0024-6115
publication_status: published
publisher: Wiley
publist_id: '7632'
quality_controlled: '1'
status: public
title: Power-free values of polynomials on symmetric varieties
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 114
year: '2017'
...
