---
_id: '14888'
abstract:
- lang: eng
  text: 'A face in a curve arrangement is called popular if it is bounded by the same
    curve multiple times. Motivated by the automatic generation of curved nonogram
    puzzles, we investigate possibilities to eliminate the popular faces in an arrangement
    by inserting a single additional curve. This turns out to be NP-hard; however,
    it becomes tractable when the number of popular faces is small: We present a probabilistic
    FPT-approach in the number of popular faces.'
acknowledgement: 'This work was initiated at the 16th European Research Week on Geometric
  Graphs in Strobl in 2019. A.W. is supported by the Austrian Science Fund (FWF):
  W1230. S.T. has been funded by the Vienna Science and Technology Fund (WWTF) [10.47379/ICT19035].
  A preliminary version of this work has been presented at the 38th European Workshop
  on Computational Geometry (EuroCG 2022) in Perugia [9]. A full version of this paper,
  which includes appendices but is otherwise identical, is available as a technical
  report [10].'
alternative_title:
- LNCS
article_processing_charge: No
arxiv: 1
author:
- first_name: Phoebe
  full_name: De Nooijer, Phoebe
  last_name: De Nooijer
- first_name: Soeren
  full_name: Terziadis, Soeren
  last_name: Terziadis
- first_name: Alexandra
  full_name: Weinberger, Alexandra
  last_name: Weinberger
- first_name: Zuzana
  full_name: Masárová, Zuzana
  id: 45CFE238-F248-11E8-B48F-1D18A9856A87
  last_name: Masárová
  orcid: 0000-0002-6660-1322
- first_name: Tamara
  full_name: Mchedlidze, Tamara
  last_name: Mchedlidze
- first_name: Maarten
  full_name: Löffler, Maarten
  last_name: Löffler
- first_name: Günter
  full_name: Rote, Günter
  last_name: Rote
citation:
  ama: 'De Nooijer P, Terziadis S, Weinberger A, et al. Removing popular faces in curve
    arrangements. In: <i>31st International Symposium on Graph Drawing and Network
    Visualization</i>. Vol 14466. Springer Nature; 2024:18-33. doi:<a href="https://doi.org/10.1007/978-3-031-49275-4_2">10.1007/978-3-031-49275-4_2</a>'
  apa: 'De Nooijer, P., Terziadis, S., Weinberger, A., Masárová, Z., Mchedlidze, T.,
    Löffler, M., &#38; Rote, G. (2024). Removing popular faces in curve arrangements.
    In <i>31st International Symposium on Graph Drawing and Network Visualization</i>
    (Vol. 14466, pp. 18–33). Isola delle Femmine, Palermo, Italy: Springer Nature.
    <a href="https://doi.org/10.1007/978-3-031-49275-4_2">https://doi.org/10.1007/978-3-031-49275-4_2</a>'
  chicago: De Nooijer, Phoebe, Soeren Terziadis, Alexandra Weinberger, Zuzana Masárová,
    Tamara Mchedlidze, Maarten Löffler, and Günter Rote. “Removing Popular Faces in Curve
    Arrangements.” In <i>31st International Symposium on Graph Drawing and Network
    Visualization</i>, 14466:18–33. Springer Nature, 2024. <a href="https://doi.org/10.1007/978-3-031-49275-4_2">https://doi.org/10.1007/978-3-031-49275-4_2</a>.
  ieee: P. De Nooijer <i>et al.</i>, “Removing popular faces in curve arrangements,”
    in <i>31st International Symposium on Graph Drawing and Network Visualization</i>,
    Isola delle Femmine, Palermo, Italy, 2024, vol. 14466, pp. 18–33.
  ista: 'De Nooijer P, Terziadis S, Weinberger A, Masárová Z, Mchedlidze T, Löffler
    M, Rote G. 2024. Removing popular faces in curve arrangements. 31st International
    Symposium on Graph Drawing and Network Visualization. GD: Graph Drawing and Network
    Visualization, LNCS, vol. 14466, 18–33.'
  mla: De Nooijer, Phoebe, et al. “Removing Popular Faces in Curve Arrangements.”
    <i>31st International Symposium on Graph Drawing and Network Visualization</i>,
    vol. 14466, Springer Nature, 2024, pp. 18–33, doi:<a href="https://doi.org/10.1007/978-3-031-49275-4_2">10.1007/978-3-031-49275-4_2</a>.
  short: P. De Nooijer, S. Terziadis, A. Weinberger, Z. Masárová, T. Mchedlidze, M.
    Löffler, G. Rote, in:, 31st International Symposium on Graph Drawing and Network
    Visualization, Springer Nature, 2024, pp. 18–33.
conference:
  end_date: 2023-09-22
  location: Isola delle Femmine, Palermo, Italy
  name: 'GD: Graph Drawing and Network Visualization'
  start_date: 2023-09-20
date_created: 2024-01-28T23:01:43Z
date_published: 2024-01-06T00:00:00Z
date_updated: 2025-09-04T11:52:35Z
day: '06'
department:
- _id: UlWa
- _id: HeEd
doi: 10.1007/978-3-031-49275-4_2
external_id:
  arxiv:
  - '2202.12175'
  isi:
  - '001207942000002'
intvolume: '     14466'
isi: 1
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://doi.org/10.48550/arXiv.2202.12175
month: '01'
oa: 1
oa_version: Preprint
page: 18-33
publication: 31st International Symposium on Graph Drawing and Network Visualization
publication_identifier:
  eissn:
  - 1611-3349
  isbn:
  - '9783031492747'
  issn:
  - 0302-9743
publication_status: published
publisher: Springer Nature
quality_controlled: '1'
scopus_import: '1'
status: public
title: Removing popular faces in curve arrangements
type: conference
user_id: 317138e5-6ab7-11ef-aa6d-ffef3953e345
volume: 14466
year: '2024'
...
---
_id: '15012'
abstract:
- lang: eng
  text: We solve a problem of Dujmović and Wood (2007) by showing that a complete
    convex geometric graph on n vertices cannot be decomposed into fewer than n-1
    star-forests, each consisting of noncrossing edges. This bound is clearly tight.
    We also discuss similar questions for abstract graphs.
acknowledgement: János Pach’s Research partially supported by European Research Council
  (ERC), grant “GeoScape” No. 882971 and by the Hungarian Science Foundation (NKFIH),
  grant K-131529. Work by Morteza Saghafian is partially supported by the European
  Research Council (ERC), grant No. 788183, and by the Wittgenstein Prize, Austrian
  Science Fund (FWF), grant No. Z 342-N31.
alternative_title:
- LNCS
article_processing_charge: No
arxiv: 1
author:
- first_name: János
  full_name: Pach, János
  id: E62E3130-B088-11EA-B919-BF823C25FEA4
  last_name: Pach
- first_name: Morteza
  full_name: Saghafian, Morteza
  id: f86f7148-b140-11ec-9577-95435b8df824
  last_name: Saghafian
- first_name: Patrick
  full_name: Schnider, Patrick
  last_name: Schnider
citation:
  ama: 'Pach J, Saghafian M, Schnider P. Decomposition of geometric graphs into star-forests.
    In: <i>31st International Symposium on Graph Drawing and Network Visualization</i>.
    Vol 14465. Springer Nature; 2024:339-346. doi:<a href="https://doi.org/10.1007/978-3-031-49272-3_23">10.1007/978-3-031-49272-3_23</a>'
  apa: 'Pach, J., Saghafian, M., &#38; Schnider, P. (2024). Decomposition of geometric
    graphs into star-forests. In <i>31st International Symposium on Graph Drawing
    and Network Visualization</i> (Vol. 14465, pp. 339–346). Isola delle Femmine,
    Palermo, Italy: Springer Nature. <a href="https://doi.org/10.1007/978-3-031-49272-3_23">https://doi.org/10.1007/978-3-031-49272-3_23</a>'
  chicago: Pach, János, Morteza Saghafian, and Patrick Schnider. “Decomposition of Geometric
    Graphs into Star-Forests.” In <i>31st International Symposium on Graph Drawing
    and Network Visualization</i>, 14465:339–46. Springer Nature, 2024. <a href="https://doi.org/10.1007/978-3-031-49272-3_23">https://doi.org/10.1007/978-3-031-49272-3_23</a>.
  ieee: J. Pach, M. Saghafian, and P. Schnider, “Decomposition of geometric graphs
    into star-forests,” in <i>31st International Symposium on Graph Drawing and Network
    Visualization</i>, Isola delle Femmine, Palermo, Italy, 2024, vol. 14465, pp.
    339–346.
  ista: 'Pach J, Saghafian M, Schnider P. 2024. Decomposition of geometric graphs
    into star-forests. 31st International Symposium on Graph Drawing and Network Visualization.
    GD: Graph Drawing and Network Visualization, LNCS, vol. 14465, 339–346.'
  mla: Pach, János, et al. “Decomposition of Geometric Graphs into Star-Forests.”
    <i>31st International Symposium on Graph Drawing and Network Visualization</i>,
    vol. 14465, Springer Nature, 2024, pp. 339–46, doi:<a href="https://doi.org/10.1007/978-3-031-49272-3_23">10.1007/978-3-031-49272-3_23</a>.
  short: J. Pach, M. Saghafian, P. Schnider, in:, 31st International Symposium on
    Graph Drawing and Network Visualization, Springer Nature, 2024, pp. 339–346.
conference:
  end_date: 2023-09-22
  location: Isola delle Femmine, Palermo, Italy
  name: 'GD: Graph Drawing and Network Visualization'
  start_date: 2023-09-20
date_created: 2024-02-18T23:01:03Z
date_published: 2024-01-01T00:00:00Z
date_updated: 2026-04-16T09:12:37Z
day: '01'
department:
- _id: HeEd
doi: 10.1007/978-3-031-49272-3_23
ec_funded: 1
external_id:
  arxiv:
  - '2306.13201'
  isi:
  - '001207939600023'
intvolume: '     14465'
isi: 1
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://doi.org/10.48550/arXiv.2306.13201
month: '01'
oa: 1
oa_version: Preprint
page: 339-346
project:
- _id: 266A2E9E-B435-11E9-9278-68D0E5697425
  call_identifier: H2020
  grant_number: '788183'
  name: Alpha Shape Theory Extended
- _id: 268116B8-B435-11E9-9278-68D0E5697425
  call_identifier: FWF
  grant_number: Z00342
  name: Mathematics, Computer Science
publication: 31st International Symposium on Graph Drawing and Network Visualization
publication_identifier:
  eisbn:
  - '9783031492723'
  eissn:
  - 1611-3349
  isbn:
  - '9783031492716'
  issn:
  - 0302-9743
publication_status: published
publisher: Springer Nature
quality_controlled: '1'
related_material:
  record:
  - id: '21253'
    relation: later_version
    status: public
scopus_import: '1'
status: public
title: Decomposition of geometric graphs into star-forests
type: conference
user_id: ba8df636-2132-11f1-aed0-ed93e2281fdd
volume: 14465
year: '2024'
...
---
OA_place: repository
_id: '15091'
abstract:
- lang: eng
  text: "Motivated by applications in the medical sciences, we study finite chromatic\r\nsets
    in Euclidean space from a topological perspective. Based on the persistent\r\nhomology
    for images, kernels and cokernels, we design provably stable\r\nhomological quantifiers
    that describe the geometric micro- and macro-structure\r\nof how the color classes
    mingle. These can be efficiently computed using\r\nchromatic variants of Delaunay
    and alpha complexes, and code that does these\r\ncomputations is provided."
article_number: '2212.03128'
article_processing_charge: No
arxiv: 1
author:
- first_name: Sebastiano
  full_name: Cultrera di Montesano, Sebastiano
  id: 34D2A09C-F248-11E8-B48F-1D18A9856A87
  last_name: Cultrera di Montesano
  orcid: 0000-0001-6249-0832
- first_name: Ondrej
  full_name: Draganov, Ondrej
  id: 2B23F01E-F248-11E8-B48F-1D18A9856A87
  last_name: Draganov
  orcid: 0000-0003-0464-3823
- first_name: Herbert
  full_name: Edelsbrunner, Herbert
  id: 3FB178DA-F248-11E8-B48F-1D18A9856A87
  last_name: Edelsbrunner
  orcid: 0000-0002-9823-6833
- first_name: Morteza
  full_name: Saghafian, Morteza
  id: f86f7148-b140-11ec-9577-95435b8df824
  last_name: Saghafian
citation:
  ama: Cultrera di Montesano S, Draganov O, Edelsbrunner H, Saghafian M. Chromatic
    alpha complexes. <i>arXiv</i>. doi:<a href="https://doi.org/10.48550/arXiv.2212.03128">10.48550/arXiv.2212.03128</a>
  apa: Cultrera di Montesano, S., Draganov, O., Edelsbrunner, H., &#38; Saghafian,
    M. (n.d.). Chromatic alpha complexes. <i>arXiv</i>. <a href="https://doi.org/10.48550/arXiv.2212.03128">https://doi.org/10.48550/arXiv.2212.03128</a>
  chicago: Cultrera di Montesano, Sebastiano, Ondrej Draganov, Herbert Edelsbrunner,
    and Morteza Saghafian. “Chromatic Alpha Complexes.” <i>ArXiv</i>, n.d. <a href="https://doi.org/10.48550/arXiv.2212.03128">https://doi.org/10.48550/arXiv.2212.03128</a>.
  ieee: S. Cultrera di Montesano, O. Draganov, H. Edelsbrunner, and M. Saghafian,
    “Chromatic alpha complexes,” <i>arXiv</i>. .
  ista: Cultrera di Montesano S, Draganov O, Edelsbrunner H, Saghafian M. Chromatic
    alpha complexes. arXiv, 2212.03128.
  mla: Cultrera di Montesano, Sebastiano, et al. “Chromatic Alpha Complexes.” <i>ArXiv</i>,
    2212.03128, doi:<a href="https://doi.org/10.48550/arXiv.2212.03128">10.48550/arXiv.2212.03128</a>.
  short: S. Cultrera di Montesano, O. Draganov, H. Edelsbrunner, M. Saghafian, ArXiv
    (n.d.).
corr_author: '1'
date_created: 2024-03-08T10:13:59Z
date_published: 2024-02-07T00:00:00Z
date_updated: 2026-04-07T12:58:47Z
day: '07'
department:
- _id: HeEd
doi: 10.48550/arXiv.2212.03128
external_id:
  arxiv:
  - '2212.03128'
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://arxiv.org/abs/2212.03128
month: '02'
oa: 1
oa_version: Preprint
publication: arXiv
publication_status: draft
related_material:
  record:
  - id: '20585'
    relation: later_version
    status: public
  - id: '18979'
    relation: dissertation_contains
    status: public
  - id: '15094'
    relation: dissertation_contains
    status: public
status: public
title: Chromatic alpha complexes
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: preprint
user_id: 8b945eb4-e2f2-11eb-945a-df72226e66a9
year: '2024'
...
---
_id: '15093'
abstract:
- lang: eng
  text: We present a dynamic data structure for maintaining the persistent homology
    of a time series of real numbers. The data structure supports local operations,
    including the insertion and deletion of an item and the cutting and concatenating
    of lists, each in time O(log n + k), in which n counts the critical items and
    k the changes in the augmented persistence diagram. To achieve this, we design
    a tailor-made tree structure with an unconventional representation, referred to
    as banana tree, which may be useful in its own right.
acknowledgement: The  first  and  second  authors  are  funded  by  the  European  Research  Council  under  the
  European Union’s Horizon 2020 research and innovation programme, ERC grant no. 788183,“Alpha
  Shape Theory Extended (Alpha)”, by the Wittgenstein Prize, FWF grant no. Z 342-N31,
  and by the DFG Collaborative Research Center TRR 109, FWF grant no. I 02979-N35.The
  third author received funding by the European Research Council under the European
  Union’s Horizon 2020research  and  innovation  programme,  ERC  grant  no.  101019564,  “The  Design  of  Modern  Fully  Dynamic  DataStructures
  (MoDynStruct)”, and by the Austrian Science Fund through the Wittgenstein Prize
  with FWF grant no. Z 422-N, and also by FWF grant no. I 5982-N, and by FWF grant
  no. P 33775-N, with additional funding from the netidee SCIENCE Stiftung, 2020–2024.  The
  fourth author is funded by the Vienna Graduate School on Computational Optimization,
  FWF project no. W1260-N35.
article_processing_charge: No
arxiv: 1
author:
- first_name: Sebastiano
  full_name: Cultrera di Montesano, Sebastiano
  id: 34D2A09C-F248-11E8-B48F-1D18A9856A87
  last_name: Cultrera di Montesano
  orcid: 0000-0001-6249-0832
- first_name: Herbert
  full_name: Edelsbrunner, Herbert
  id: 3FB178DA-F248-11E8-B48F-1D18A9856A87
  last_name: Edelsbrunner
  orcid: 0000-0002-9823-6833
- first_name: Monika H
  full_name: Henzinger, Monika H
  id: 540c9bbd-f2de-11ec-812d-d04a5be85630
  last_name: Henzinger
  orcid: 0000-0002-5008-6530
- first_name: Lara
  full_name: Ost, Lara
  last_name: Ost
citation:
  ama: 'Cultrera di Montesano S, Edelsbrunner H, Henzinger M, Ost L. Dynamically maintaining
    the persistent homology of time series. In: Woodruff DP, ed. <i>Proceedings of
    the 2024 Annual ACM-SIAM Symposium on Discrete Algorithms (SODA)</i>. Society
    for Industrial and Applied Mathematics; 2024:243-295. doi:<a href="https://doi.org/10.1137/1.9781611977912.11">10.1137/1.9781611977912.11</a>'
  apa: 'Cultrera di Montesano, S., Edelsbrunner, H., Henzinger, M., &#38; Ost, L.
    (2024). Dynamically maintaining the persistent homology of time series. In D.
    P. Woodruff (Ed.), <i>Proceedings of the 2024 Annual ACM-SIAM Symposium on Discrete
    Algorithms (SODA)</i> (pp. 243–295). Alexandria, VA, USA: Society for Industrial
    and Applied Mathematics. <a href="https://doi.org/10.1137/1.9781611977912.11">https://doi.org/10.1137/1.9781611977912.11</a>'
  chicago: Cultrera di Montesano, Sebastiano, Herbert Edelsbrunner, Monika Henzinger,
    and Lara Ost. “Dynamically Maintaining the Persistent Homology of Time Series.”
    In <i>Proceedings of the 2024 Annual ACM-SIAM Symposium on Discrete Algorithms
    (SODA)</i>, edited by David P. Woodruff, 243–95. Society for Industrial and Applied
    Mathematics, 2024. <a href="https://doi.org/10.1137/1.9781611977912.11">https://doi.org/10.1137/1.9781611977912.11</a>.
  ieee: S. Cultrera di Montesano, H. Edelsbrunner, M. Henzinger, and L. Ost, “Dynamically
    maintaining the persistent homology of time series,” in <i>Proceedings of the
    2024 Annual ACM-SIAM Symposium on Discrete Algorithms (SODA)</i>, Alexandria,
    VA, USA, 2024, pp. 243–295.
  ista: 'Cultrera di Montesano S, Edelsbrunner H, Henzinger M, Ost L. 2024. Dynamically
    maintaining the persistent homology of time series. Proceedings of the 2024 Annual
    ACM-SIAM Symposium on Discrete Algorithms (SODA). SODA: Symposium on Discrete
    Algorithms, 243–295.'
  mla: Cultrera di Montesano, Sebastiano, et al. “Dynamically Maintaining the Persistent
    Homology of Time Series.” <i>Proceedings of the 2024 Annual ACM-SIAM Symposium
    on Discrete Algorithms (SODA)</i>, edited by David P. Woodruff, Society for Industrial
    and Applied Mathematics, 2024, pp. 243–95, doi:<a href="https://doi.org/10.1137/1.9781611977912.11">10.1137/1.9781611977912.11</a>.
  short: S. Cultrera di Montesano, H. Edelsbrunner, M. Henzinger, L. Ost, in:, D.P.
    Woodruff (Ed.), Proceedings of the 2024 Annual ACM-SIAM Symposium on Discrete
    Algorithms (SODA), Society for Industrial and Applied Mathematics, 2024, pp. 243–295.
conference:
  end_date: 2024-01-10
  location: Alexandria, VA, USA
  name: 'SODA: Symposium on Discrete Algorithms'
  start_date: 2024-01-07
corr_author: '1'
date_created: 2024-03-08T10:27:39Z
date_published: 2024-01-04T00:00:00Z
date_updated: 2026-04-07T12:58:47Z
day: '04'
department:
- _id: HeEd
- _id: MoHe
doi: 10.1137/1.9781611977912.11
ec_funded: 1
editor:
- first_name: David P.
  full_name: Woodruff, David P.
  last_name: Woodruff
external_id:
  arxiv:
  - '2311.01115'
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://arxiv.org/abs/2311.01115
month: '01'
oa: 1
oa_version: Preprint
page: 243 - 295
project:
- _id: 266A2E9E-B435-11E9-9278-68D0E5697425
  call_identifier: H2020
  grant_number: '788183'
  name: Alpha Shape Theory Extended
- _id: 268116B8-B435-11E9-9278-68D0E5697425
  call_identifier: FWF
  grant_number: Z00342
  name: Mathematics, Computer Science
- _id: bd9ca328-d553-11ed-ba76-dc4f890cfe62
  call_identifier: H2020
  grant_number: '101019564'
  name: The design and evaluation of modern fully dynamic data structures
- _id: 34def286-11ca-11ed-8bc3-da5948e1613c
  grant_number: Z00422
  name: Efficient algorithms
- _id: bd9e3a2e-d553-11ed-ba76-8aa684ce17fe
  grant_number: P33775
  name: Fast Algorithms for a Reactive Network Layer
publication: Proceedings of the 2024 Annual ACM-SIAM Symposium on Discrete Algorithms
  (SODA)
publication_identifier:
  eisbn:
  - '9781611977912'
publication_status: published
publisher: Society for Industrial and Applied Mathematics
quality_controlled: '1'
related_material:
  record:
  - id: '15094'
    relation: dissertation_contains
    status: public
scopus_import: '1'
status: public
title: Dynamically maintaining the persistent homology of time series
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
year: '2024'
...
---
OA_place: publisher
_id: '15094'
abstract:
- lang: eng
  text: "Point sets, geometric networks, and arrangements of hyperplanes are fundamental
    objects in\r\ndiscrete geometry that have captivated mathematicians for centuries,
    if not millennia. This\r\nthesis seeks to cast new light on these structures by
    illustrating specific instances where a\r\ntopological perspective, specifically
    through discrete Morse theory and persistent homology,\r\nprovides valuable insights.\r\n\r\nAt
    first glance, the topology of these geometric objects might seem uneventful: point
    sets\r\nessentially lack of topology, arrangements of hyperplanes are a decomposition
    of Rd, which\r\nis a contractible space, and the topology of a network primarily
    involves the enumeration\r\nof connected components and cycles within the network.
    However, beneath this apparent\r\nsimplicity, there lies an array of intriguing
    structures, a small subset of which will be uncovered\r\nin this thesis.\r\n\r\nFocused
    on three case studies, each addressing one of the mentioned objects, this work\r\nwill
    showcase connections that intertwine topology with diverse fields such as combinatorial\r\ngeometry,
    algorithms and data structures, and emerging applications like spatial biology.\r\n\r\n"
alternative_title:
- ISTA Thesis
article_processing_charge: No
author:
- first_name: Sebastiano
  full_name: Cultrera di Montesano, Sebastiano
  id: 34D2A09C-F248-11E8-B48F-1D18A9856A87
  last_name: Cultrera di Montesano
  orcid: 0000-0001-6249-0832
citation:
  ama: Cultrera di Montesano S. Persistence and Morse theory for discrete geometric
    structures. 2024. doi:<a href="https://doi.org/10.15479/at:ista:15094">10.15479/at:ista:15094</a>
  apa: Cultrera di Montesano, S. (2024). <i>Persistence and Morse theory for discrete
    geometric structures</i>. Institute of Science and Technology Austria. <a href="https://doi.org/10.15479/at:ista:15094">https://doi.org/10.15479/at:ista:15094</a>
  chicago: Cultrera di Montesano, Sebastiano. “Persistence and Morse Theory for Discrete
    Geometric Structures.” Institute of Science and Technology Austria, 2024. <a href="https://doi.org/10.15479/at:ista:15094">https://doi.org/10.15479/at:ista:15094</a>.
  ieee: S. Cultrera di Montesano, “Persistence and Morse theory for discrete geometric
    structures,” Institute of Science and Technology Austria, 2024.
  ista: Cultrera di Montesano S. 2024. Persistence and Morse theory for discrete geometric
    structures. Institute of Science and Technology Austria.
  mla: Cultrera di Montesano, Sebastiano. <i>Persistence and Morse Theory for Discrete
    Geometric Structures</i>. Institute of Science and Technology Austria, 2024, doi:<a
    href="https://doi.org/10.15479/at:ista:15094">10.15479/at:ista:15094</a>.
  short: S. Cultrera di Montesano, Persistence and Morse Theory for Discrete Geometric
    Structures, Institute of Science and Technology Austria, 2024.
corr_author: '1'
date_created: 2024-03-08T15:28:10Z
date_published: 2024-03-08T00:00:00Z
date_updated: 2026-04-07T12:58:48Z
day: '08'
ddc:
- '514'
- '500'
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degree_awarded: PhD
department:
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doi: 10.15479/at:ista:15094
ec_funded: 1
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status: public
supervisor:
- first_name: Herbert
  full_name: Edelsbrunner, Herbert
  id: 3FB178DA-F248-11E8-B48F-1D18A9856A87
  last_name: Edelsbrunner
  orcid: 0000-0002-9823-6833
title: Persistence and Morse theory for discrete geometric structures
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---
OA_place: publisher
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_id: '15247'
abstract:
- lang: eng
  text: Extending the notion of sunflowers, we call a family of at least two sets
    an odd-sunflower if every element of the underlying set is contained in an odd
    number of sets or in none of them. It follows from the Erdős–Szemerédi conjecture,
    recently proved by Naslund and Sawin, that there is a constant <2 such that every
    family of subsets of an n-element set that contains no odd-sunflower consists
    of at most n sets. We construct such families of size at least 1.5021n. We also
    characterize minimal odd-sunflowers of triples.
acknowledgement: We are grateful to Balázs Keszegh, and to the members of the Miklós
  Schweitzer Competition committee of 2022 for valuable discussions, and Shira Zerbib
  for pointing out several important mathematical typos.
article_number: '105889'
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: Peter
  full_name: Frankl, Peter
  last_name: Frankl
- first_name: János
  full_name: Pach, János
  id: E62E3130-B088-11EA-B919-BF823C25FEA4
  last_name: Pach
- first_name: Dömötör
  full_name: Pálvölgyi, Dömötör
  last_name: Pálvölgyi
citation:
  ama: Frankl P, Pach J, Pálvölgyi D. Odd-sunflowers. <i>Journal of Combinatorial
    Theory, Series A</i>. 2024;206(8). doi:<a href="https://doi.org/10.1016/j.jcta.2024.105889">10.1016/j.jcta.2024.105889</a>
  apa: Frankl, P., Pach, J., &#38; Pálvölgyi, D. (2024). Odd-sunflowers. <i>Journal
    of Combinatorial Theory, Series A</i>. Elsevier. <a href="https://doi.org/10.1016/j.jcta.2024.105889">https://doi.org/10.1016/j.jcta.2024.105889</a>
  chicago: Frankl, Peter, János Pach, and Dömötör Pálvölgyi. “Odd-Sunflowers.” <i>Journal
    of Combinatorial Theory, Series A</i>. Elsevier, 2024. <a href="https://doi.org/10.1016/j.jcta.2024.105889">https://doi.org/10.1016/j.jcta.2024.105889</a>.
  ieee: P. Frankl, J. Pach, and D. Pálvölgyi, “Odd-sunflowers,” <i>Journal of Combinatorial
    Theory, Series A</i>, vol. 206, no. 8. Elsevier, 2024.
  ista: Frankl P, Pach J, Pálvölgyi D. 2024. Odd-sunflowers. Journal of Combinatorial
    Theory, Series A. 206(8), 105889.
  mla: Frankl, Peter, et al. “Odd-Sunflowers.” <i>Journal of Combinatorial Theory,
    Series A</i>, vol. 206, no. 8, 105889, Elsevier, 2024, doi:<a href="https://doi.org/10.1016/j.jcta.2024.105889">10.1016/j.jcta.2024.105889</a>.
  short: P. Frankl, J. Pach, D. Pálvölgyi, Journal of Combinatorial Theory, Series
    A 206 (2024).
corr_author: '1'
date_created: 2024-03-31T22:01:11Z
date_published: 2024-08-01T00:00:00Z
date_updated: 2025-09-04T13:20:39Z
day: '01'
ddc:
- '510'
department:
- _id: HeEd
doi: 10.1016/j.jcta.2024.105889
external_id:
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  - '2310.16701'
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month: '08'
oa: 1
oa_version: Published Version
publication: Journal of Combinatorial Theory, Series A
publication_identifier:
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publication_status: published
publisher: Elsevier
quality_controlled: '1'
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title: Odd-sunflowers
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---
OA_place: publisher
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_id: '15380'
abstract:
- lang: eng
  text: The depth of a cell in an arrangement of n (non-vertical) great-spheres in
    Sd is the number of great-spheres that pass above the cell. We prove Euler-type
    relations, which imply extensions of the classic Dehn–Sommerville relations for
    convex polytopes to sublevel sets of the depth function, and we use the relations
    to extend the expressions for the number of faces of neighborly polytopes to the
    number of cells of levels in neighborly arrangements.
acknowledgement: "The authors thank Uli Wagner and Emo Welzl for comments on an earlier
  version of this paper, and for pointing out related work in the prior literature.\r\nOpen
  access funding provided by Institute of Science and Technology (IST Austria). This
  project has received funding from the European Research Council (ERC) under the
  European Union’s Horizon 2020 research and innovation programme, Grant No. 788183,
  from the Wittgenstein Prize, Austrian Science Fund (FWF), Grant No. Z 342-N31, and
  from the DFG Collaborative Research Center TRR 109, ‘Discretization in Geometry
  and Dynamics’, Austrian Science Fund (FWF), Grant No. I 02979-N35."
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article_type: original
author:
- first_name: Ranita
  full_name: Biswas, Ranita
  id: 3C2B033E-F248-11E8-B48F-1D18A9856A87
  last_name: Biswas
  orcid: 0000-0002-5372-7890
- first_name: Sebastiano
  full_name: Cultrera Di Montesano, Sebastiano
  id: 34D2A09C-F248-11E8-B48F-1D18A9856A87
  last_name: Cultrera Di Montesano
  orcid: 0000-0001-6249-0832
- first_name: Herbert
  full_name: Edelsbrunner, Herbert
  id: 3FB178DA-F248-11E8-B48F-1D18A9856A87
  last_name: Edelsbrunner
  orcid: 0000-0002-9823-6833
- first_name: Morteza
  full_name: Saghafian, Morteza
  id: f86f7148-b140-11ec-9577-95435b8df824
  last_name: Saghafian
citation:
  ama: 'Biswas R, Cultrera di Montesano S, Edelsbrunner H, Saghafian M. Depth in arrangements:
    Dehn–Sommerville–Euler relations with applications. <i>Journal of Applied and
    Computational Topology</i>. 2024;8:557-578. doi:<a href="https://doi.org/10.1007/s41468-024-00173-w">10.1007/s41468-024-00173-w</a>'
  apa: 'Biswas, R., Cultrera di Montesano, S., Edelsbrunner, H., &#38; Saghafian,
    M. (2024). Depth in arrangements: Dehn–Sommerville–Euler relations with applications.
    <i>Journal of Applied and Computational Topology</i>. Springer Nature. <a href="https://doi.org/10.1007/s41468-024-00173-w">https://doi.org/10.1007/s41468-024-00173-w</a>'
  chicago: 'Biswas, Ranita, Sebastiano Cultrera di Montesano, Herbert Edelsbrunner,
    and Morteza Saghafian. “Depth in Arrangements: Dehn–Sommerville–Euler Relations
    with Applications.” <i>Journal of Applied and Computational Topology</i>. Springer
    Nature, 2024. <a href="https://doi.org/10.1007/s41468-024-00173-w">https://doi.org/10.1007/s41468-024-00173-w</a>.'
  ieee: 'R. Biswas, S. Cultrera di Montesano, H. Edelsbrunner, and M. Saghafian, “Depth
    in arrangements: Dehn–Sommerville–Euler relations with applications,” <i>Journal
    of Applied and Computational Topology</i>, vol. 8. Springer Nature, pp. 557–578,
    2024.'
  ista: 'Biswas R, Cultrera di Montesano S, Edelsbrunner H, Saghafian M. 2024. Depth
    in arrangements: Dehn–Sommerville–Euler relations with applications. Journal of
    Applied and Computational Topology. 8, 557–578.'
  mla: 'Biswas, Ranita, et al. “Depth in Arrangements: Dehn–Sommerville–Euler Relations
    with Applications.” <i>Journal of Applied and Computational Topology</i>, vol.
    8, Springer Nature, 2024, pp. 557–78, doi:<a href="https://doi.org/10.1007/s41468-024-00173-w">10.1007/s41468-024-00173-w</a>.'
  short: R. Biswas, S. Cultrera di Montesano, H. Edelsbrunner, M. Saghafian, Journal
    of Applied and Computational Topology 8 (2024) 557–578.
corr_author: '1'
date_created: 2024-05-12T22:01:03Z
date_published: 2024-09-01T00:00:00Z
date_updated: 2025-05-14T09:27:57Z
day: '01'
ddc:
- '510'
department:
- _id: HeEd
doi: 10.1007/s41468-024-00173-w
ec_funded: 1
external_id:
  pmid:
  - '39308789'
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month: '09'
oa: 1
oa_version: Published Version
page: 557-578
pmid: 1
project:
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  call_identifier: H2020
  grant_number: '788183'
  name: Alpha Shape Theory Extended
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  name: Persistence and stability of geometric complexes
publication: Journal of Applied and Computational Topology
publication_identifier:
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  issn:
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publication_status: published
publisher: Springer Nature
quality_controlled: '1'
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scopus_import: '1'
status: public
title: 'Depth in arrangements: Dehn–Sommerville–Euler relations with applications'
tmp:
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type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 8
year: '2024'
...
---
_id: '17144'
abstract:
- lang: eng
  text: "We prove that the medial axis of closed sets is Hausdorff stable in the following
    sense: Let \U0001D4AE ⊆ ℝ^d be a fixed closed set that contains a bounding sphere.
    That is, the bounding sphere is part of the set \U0001D4AE. Consider the space
    of C^{1,1} diffeomorphisms of ℝ^d to itself, which keep the bounding sphere invariant.
    The map from this space of diffeomorphisms (endowed with a Banach norm) to the
    space of closed subsets of ℝ^d (endowed with the Hausdorff distance), mapping
    a diffeomorphism F to the closure of the medial axis of F(\U0001D4AE), is Lipschitz.
    This extends a previous stability result of Chazal and Soufflet on the stability
    of the medial axis of C² manifolds under C² ambient diffeomorphisms."
acknowledgement: "This research has been supported by the European Research Council
  (ERC), grant No. 788183, by the Wittgenstein Prize, Austrian Science Fund (FWF),
  grant No. Z 342-N31, and by the DFG Collaborative Research Center TRR 109, Austrian
  Science Fund (FWF), grant No. I 02979-N35.\r\nSupported by the European Union’s
  Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie
  grant agreement No. 754411, the Austrian science fund (FWF) grant No. M-3073, and
  the welcome package from IDEX of the Université Cô d'Azur.\r\nWe are greatly indebted
  to Fred Chazal for sharing his insights. We further thank Erin Chambers, Christopher
  Fillmore, and Elizabeth Stephenson for early discussions and all members of the
  Edelsbrunner group (Institute of Science and Technology Austria) and the Datashape
  team (Inria) for the atmosphere in which this research was conducted."
alternative_title:
- LIPIcs
article_number: '69'
article_processing_charge: No
arxiv: 1
author:
- first_name: Hana
  full_name: Kourimska, Hana
  id: D9B8E14C-3C26-11EA-98F5-1F833DDC885E
  last_name: Kourimska
  orcid: 0000-0001-7841-0091
- first_name: André
  full_name: Lieutier, André
  last_name: Lieutier
- first_name: Mathijs
  full_name: Wintraecken, Mathijs
  id: 307CFBC8-F248-11E8-B48F-1D18A9856A87
  last_name: Wintraecken
  orcid: 0000-0002-7472-2220
citation:
  ama: 'Kourimska H, Lieutier A, Wintraecken M. The medial axis of any closed bounded
    set Is Lipschitz stable with respect to the Hausdorff distance Under ambient diffeomorphisms.
    In: <i>40th International Symposium on Computational Geometry</i>. Vol 293. Schloss
    Dagstuhl - Leibniz-Zentrum für Informatik; 2024. doi:<a href="https://doi.org/10.4230/LIPIcs.SoCG.2024.69">10.4230/LIPIcs.SoCG.2024.69</a>'
  apa: 'Kourimska, H., Lieutier, A., &#38; Wintraecken, M. (2024). The medial axis
    of any closed bounded set Is Lipschitz stable with respect to the Hausdorff distance
    Under ambient diffeomorphisms. In <i>40th International Symposium on Computational
    Geometry</i> (Vol. 293). Athens, Greece: Schloss Dagstuhl - Leibniz-Zentrum für
    Informatik. <a href="https://doi.org/10.4230/LIPIcs.SoCG.2024.69">https://doi.org/10.4230/LIPIcs.SoCG.2024.69</a>'
  chicago: Kourimska, Hana, André Lieutier, and Mathijs Wintraecken. “The Medial Axis
    of Any Closed Bounded Set Is Lipschitz Stable with Respect to the Hausdorff Distance
    Under Ambient Diffeomorphisms.” In <i>40th International Symposium on Computational
    Geometry</i>, Vol. 293. Schloss Dagstuhl - Leibniz-Zentrum für Informatik, 2024.
    <a href="https://doi.org/10.4230/LIPIcs.SoCG.2024.69">https://doi.org/10.4230/LIPIcs.SoCG.2024.69</a>.
  ieee: H. Kourimska, A. Lieutier, and M. Wintraecken, “The medial axis of any closed
    bounded set Is Lipschitz stable with respect to the Hausdorff distance Under ambient
    diffeomorphisms,” in <i>40th International Symposium on Computational Geometry</i>,
    Athens, Greece, 2024, vol. 293.
  ista: 'Kourimska H, Lieutier A, Wintraecken M. 2024. The medial axis of any closed
    bounded set Is Lipschitz stable with respect to the Hausdorff distance Under ambient
    diffeomorphisms. 40th International Symposium on Computational Geometry. SoCG:
    Symposium on Computational Geometry, LIPIcs, vol. 293, 69.'
  mla: Kourimska, Hana, et al. “The Medial Axis of Any Closed Bounded Set Is Lipschitz
    Stable with Respect to the Hausdorff Distance Under Ambient Diffeomorphisms.”
    <i>40th International Symposium on Computational Geometry</i>, vol. 293, 69, Schloss
    Dagstuhl - Leibniz-Zentrum für Informatik, 2024, doi:<a href="https://doi.org/10.4230/LIPIcs.SoCG.2024.69">10.4230/LIPIcs.SoCG.2024.69</a>.
  short: H. Kourimska, A. Lieutier, M. Wintraecken, in:, 40th International Symposium
    on Computational Geometry, Schloss Dagstuhl - Leibniz-Zentrum für Informatik,
    2024.
conference:
  end_date: 2024-06-14
  location: Athens, Greece
  name: 'SoCG: Symposium on Computational Geometry'
date_created: 2024-06-16T22:01:06Z
date_published: 2024-06-01T00:00:00Z
date_updated: 2025-04-15T07:16:58Z
day: '01'
ddc:
- '510'
department:
- _id: HeEd
doi: 10.4230/LIPIcs.SoCG.2024.69
ec_funded: 1
external_id:
  arxiv:
  - '2212.01118'
file:
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  file_id: '17150'
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  file_size: 1612558
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  success: 1
file_date_updated: 2024-06-17T08:33:40Z
has_accepted_license: '1'
intvolume: '       293'
language:
- iso: eng
month: '06'
oa: 1
oa_version: Published Version
project:
- _id: 266A2E9E-B435-11E9-9278-68D0E5697425
  call_identifier: H2020
  grant_number: '788183'
  name: Alpha Shape Theory Extended
- _id: 268116B8-B435-11E9-9278-68D0E5697425
  call_identifier: FWF
  grant_number: Z00342
  name: Mathematics, Computer Science
- _id: 2561EBF4-B435-11E9-9278-68D0E5697425
  call_identifier: FWF
  grant_number: I02979-N35
  name: Persistence and stability of geometric complexes
- _id: 260C2330-B435-11E9-9278-68D0E5697425
  call_identifier: H2020
  grant_number: '754411'
  name: ISTplus - Postdoctoral Fellowships
- _id: fc390959-9c52-11eb-aca3-afa58bd282b2
  grant_number: M03073
  name: Learning and triangulating manifolds via collapses
publication: 40th International Symposium on Computational Geometry
publication_identifier:
  isbn:
  - '9783959773164'
  issn:
  - 1868-8969
publication_status: published
publisher: Schloss Dagstuhl - Leibniz-Zentrum für Informatik
quality_controlled: '1'
scopus_import: '1'
status: public
title: The medial axis of any closed bounded set Is Lipschitz stable with respect
  to the Hausdorff distance Under ambient diffeomorphisms
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
volume: 293
year: '2024'
...
---
_id: '17145'
abstract:
- lang: eng
  text: Grid peeling is the process of repeatedly removing the convex hull vertices
    of the grid points that lie inside a given convex curve. It has been conjectured
    that, for a more and more refined grid, grid peeling converges to a continuous
    process, the affine curve-shortening flow, which deforms the curve based on the
    curvature. We prove this conjecture for one class of curves, parabolas with a
    vertical axis, and we determine the value of the constant factor in the formula
    that relates the two processes.
acknowledgement: Part of this work was done while G.R. enjoyed the hospitality of
  the Institute of Science and Technology Austria (ISTA) as a visiting professor during
  his sabbatical in the winter semester 2022/23.
alternative_title:
- LIPIcs
article_number: '76'
article_processing_charge: No
arxiv: 1
author:
- first_name: Günter
  full_name: Rote, Günter
  last_name: Rote
- first_name: Moritz
  full_name: Rüber, Moritz
  last_name: Rüber
- first_name: Morteza
  full_name: Saghafian, Morteza
  id: f86f7148-b140-11ec-9577-95435b8df824
  last_name: Saghafian
citation:
  ama: 'Rote G, Rüber M, Saghafian M. Grid peeling of parabolas. In: <i>40th International
    Symposium on Computational Geometry</i>. Vol 293. Schloss Dagstuhl - Leibniz-Zentrum
    für Informatik; 2024. doi:<a href="https://doi.org/10.4230/LIPIcs.SoCG.2024.76">10.4230/LIPIcs.SoCG.2024.76</a>'
  apa: 'Rote, G., Rüber, M., &#38; Saghafian, M. (2024). Grid peeling of parabolas.
    In <i>40th International Symposium on Computational Geometry</i> (Vol. 293). Athens,
    Greece: Schloss Dagstuhl - Leibniz-Zentrum für Informatik. <a href="https://doi.org/10.4230/LIPIcs.SoCG.2024.76">https://doi.org/10.4230/LIPIcs.SoCG.2024.76</a>'
  chicago: Rote, Günter, Moritz Rüber, and Morteza Saghafian. “Grid Peeling of Parabolas.”
    In <i>40th International Symposium on Computational Geometry</i>, Vol. 293. Schloss
    Dagstuhl - Leibniz-Zentrum für Informatik, 2024. <a href="https://doi.org/10.4230/LIPIcs.SoCG.2024.76">https://doi.org/10.4230/LIPIcs.SoCG.2024.76</a>.
  ieee: G. Rote, M. Rüber, and M. Saghafian, “Grid peeling of parabolas,” in <i>40th
    International Symposium on Computational Geometry</i>, Athens, Greece, 2024, vol.
    293.
  ista: 'Rote G, Rüber M, Saghafian M. 2024. Grid peeling of parabolas. 40th International
    Symposium on Computational Geometry. SoCG: Symposium on Computational Geometry,
    LIPIcs, vol. 293, 76.'
  mla: Rote, Günter, et al. “Grid Peeling of Parabolas.” <i>40th International Symposium
    on Computational Geometry</i>, vol. 293, 76, Schloss Dagstuhl - Leibniz-Zentrum
    für Informatik, 2024, doi:<a href="https://doi.org/10.4230/LIPIcs.SoCG.2024.76">10.4230/LIPIcs.SoCG.2024.76</a>.
  short: G. Rote, M. Rüber, M. Saghafian, in:, 40th International Symposium on Computational
    Geometry, Schloss Dagstuhl - Leibniz-Zentrum für Informatik, 2024.
conference:
  end_date: 2024-06-14
  location: Athens, Greece
  name: 'SoCG: Symposium on Computational Geometry'
  start_date: 2024-06-11
date_created: 2024-06-16T22:01:06Z
date_published: 2024-06-01T00:00:00Z
date_updated: 2024-06-17T08:41:56Z
day: '01'
ddc:
- '510'
department:
- _id: HeEd
doi: 10.4230/LIPIcs.SoCG.2024.76
external_id:
  arxiv:
  - '2402.15787'
file:
- access_level: open_access
  checksum: fbad1de06383a6b7e8a1cb3e8c7205ce
  content_type: application/pdf
  creator: dernst
  date_created: 2024-06-17T08:40:04Z
  date_updated: 2024-06-17T08:40:04Z
  file_id: '17151'
  file_name: 2024_LIPICS_Rote.pdf
  file_size: 1430896
  relation: main_file
  success: 1
file_date_updated: 2024-06-17T08:40:04Z
has_accepted_license: '1'
intvolume: '       293'
language:
- iso: eng
month: '06'
oa: 1
oa_version: Published Version
publication: 40th International Symposium on Computational Geometry
publication_identifier:
  isbn:
  - '9783959773164'
  issn:
  - 1868-8969
publication_status: published
publisher: Schloss Dagstuhl - Leibniz-Zentrum für Informatik
quality_controlled: '1'
scopus_import: '1'
status: public
title: Grid peeling of parabolas
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
volume: 293
year: '2024'
...
---
_id: '17146'
abstract:
- lang: eng
  text: The Upper Bound Theorem for convex polytopes implies that the p-th Betti number
    of the Čech complex of any set of N points in ℝ^d and any radius satisfies β_p
    = O(N^m), with m = min{p+1, ⌈d/2⌉}. We construct sets in even and odd dimensions,
    which prove that this upper bound is asymptotically tight. For example, we describe
    a set of N = 2(n+1) points in ℝ³ and two radii such that the first Betti number
    of the Čech complex at one radius is (n+1)² - 1, and the second Betti number of
    the Čech complex at the other radius is n². In particular, there is an arrangement
    of n contruent balls in ℝ³ that enclose a quadratic number of voids, which answers
    a long-standing open question in computational geometry.
acknowledgement: "The first author is supported by the European Research Council (ERC),
  grant no. 788183, and by the DFG Collaborative Research Center TRR 109, Austrian
  Science Fund (FWF), grant no. {I 02979-N35.} The second author is supported by the
  European Research Council (ERC), grant \"GeoScape\" and by the Hungarian Science
  Foundation (NKFIH), grant K-131529. Both authors are supported by the Wittgenstein
  Prize, Austrian Science Fund (FWF), grant no. Z 342-N31.\r\nThe authors thank Matt
  Kahle for communicating the question about extremal Čech complexes, Ben Schweinhart
  for early discussions on the linked circles construction in three dimensions, and
  Gábor Tardos for helpful remarks and suggestions."
alternative_title:
- LIPIcs
article_number: '53'
article_processing_charge: No
arxiv: 1
author:
- first_name: Herbert
  full_name: Edelsbrunner, Herbert
  id: 3FB178DA-F248-11E8-B48F-1D18A9856A87
  last_name: Edelsbrunner
  orcid: 0000-0002-9823-6833
- first_name: János
  full_name: Pach, János
  id: E62E3130-B088-11EA-B919-BF823C25FEA4
  last_name: Pach
citation:
  ama: 'Edelsbrunner H, Pach J. Maximum Betti numbers of Čech complexes. In: <i>40th
    International Symposium on Computational Geometry</i>. Vol 293. Schloss Dagstuhl
    - Leibniz-Zentrum für Informatik; 2024. doi:<a href="https://doi.org/10.4230/LIPIcs.SoCG.2024.53">10.4230/LIPIcs.SoCG.2024.53</a>'
  apa: 'Edelsbrunner, H., &#38; Pach, J. (2024). Maximum Betti numbers of Čech complexes.
    In <i>40th International Symposium on Computational Geometry</i> (Vol. 293). Athens,
    Greece: Schloss Dagstuhl - Leibniz-Zentrum für Informatik. <a href="https://doi.org/10.4230/LIPIcs.SoCG.2024.53">https://doi.org/10.4230/LIPIcs.SoCG.2024.53</a>'
  chicago: Edelsbrunner, Herbert, and János Pach. “Maximum Betti Numbers of Čech Complexes.”
    In <i>40th International Symposium on Computational Geometry</i>, Vol. 293. Schloss
    Dagstuhl - Leibniz-Zentrum für Informatik, 2024. <a href="https://doi.org/10.4230/LIPIcs.SoCG.2024.53">https://doi.org/10.4230/LIPIcs.SoCG.2024.53</a>.
  ieee: H. Edelsbrunner and J. Pach, “Maximum Betti numbers of Čech complexes,” in
    <i>40th International Symposium on Computational Geometry</i>, Athens, Greece,
    2024, vol. 293.
  ista: 'Edelsbrunner H, Pach J. 2024. Maximum Betti numbers of Čech complexes. 40th
    International Symposium on Computational Geometry. SoCG: Symposium on Computational
    Geometry, LIPIcs, vol. 293, 53.'
  mla: Edelsbrunner, Herbert, and János Pach. “Maximum Betti Numbers of Čech Complexes.”
    <i>40th International Symposium on Computational Geometry</i>, vol. 293, 53, Schloss
    Dagstuhl - Leibniz-Zentrum für Informatik, 2024, doi:<a href="https://doi.org/10.4230/LIPIcs.SoCG.2024.53">10.4230/LIPIcs.SoCG.2024.53</a>.
  short: H. Edelsbrunner, J. Pach, in:, 40th International Symposium on Computational
    Geometry, Schloss Dagstuhl - Leibniz-Zentrum für Informatik, 2024.
conference:
  end_date: 2024-06-14
  location: Athens, Greece
  name: 'SoCG: Symposium on Computational Geometry'
  start_date: 2024-06-11
date_created: 2024-06-16T22:01:06Z
date_published: 2024-06-01T00:00:00Z
date_updated: 2025-12-01T15:19:20Z
day: '01'
ddc:
- '510'
department:
- _id: HeEd
doi: 10.4230/LIPIcs.SoCG.2024.53
ec_funded: 1
external_id:
  arxiv:
  - '2310.14801'
file:
- access_level: open_access
  checksum: 5442d44fb89d77477a87668d6e61aac9
  content_type: application/pdf
  creator: dernst
  date_created: 2024-06-17T08:46:33Z
  date_updated: 2024-06-17T08:46:33Z
  file_id: '17152'
  file_name: 2024_LIPICS_Edelsbrunner.pdf
  file_size: 766562
  relation: main_file
  success: 1
file_date_updated: 2024-06-17T08:46:33Z
has_accepted_license: '1'
intvolume: '       293'
language:
- iso: eng
month: '06'
oa: 1
oa_version: Published Version
project:
- _id: 266A2E9E-B435-11E9-9278-68D0E5697425
  call_identifier: H2020
  grant_number: '788183'
  name: Alpha Shape Theory Extended
- _id: 2561EBF4-B435-11E9-9278-68D0E5697425
  call_identifier: FWF
  grant_number: I02979-N35
  name: Persistence and stability of geometric complexes
- _id: 268116B8-B435-11E9-9278-68D0E5697425
  call_identifier: FWF
  grant_number: Z00342
  name: Mathematics, Computer Science
publication: 40th International Symposium on Computational Geometry
publication_identifier:
  isbn:
  - '9783959773164'
  issn:
  - 1868-8969
publication_status: published
publisher: Schloss Dagstuhl - Leibniz-Zentrum für Informatik
quality_controlled: '1'
related_material:
  record:
  - id: '20657'
    relation: later_version
    status: public
scopus_import: '1'
status: public
title: Maximum Betti numbers of Čech complexes
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
volume: 293
year: '2024'
...
---
_id: '17170'
abstract:
- lang: eng
  text: "In this article we extend and strengthen the seminal work by Niyogi, Smale,
    and Weinberger on the learning of the homotopy type from a sample of an underlying
    space. In their work, Niyogi, Smale, and Weinberger studied samples of C² manifolds
    with positive reach embedded in ℝ^d. We extend their results in the following
    ways: - As the ambient space we consider both ℝ^d and Riemannian manifolds with
    lower bounded sectional curvature. - In both types of ambient spaces, we study
    sets of positive reach - a significantly more general setting than C² manifolds
    - as well as general manifolds of positive reach. - The sample P of a set (or
    a manifold) \U0001D4AE of positive reach may be noisy. We work with two one-sided
    Hausdorff distances - ε and δ - between P and \U0001D4AE. We provide tight bounds
    in terms of ε and δ, that guarantee that there exists a parameter r such that
    the union of balls of radius r centred at the sample P deformation-retracts to
    \U0001D4AE. We exhibit their tightness by an explicit construction. We carefully
    distinguish the roles of δ and ε. This is not only essential to achieve tight
    bounds, but also sensible in practical situations, since it allows one to adapt
    the bound according to sample density and the amount of noise present in the sample
    separately."
acknowledgement: "This research has been supported by the European Research Council
  (ERC), grant No. 788183, by the Wittgenstein Prize, Austrian Science Fund (FWF),
  grant No. Z 342-N31, and by the DFG Collaborative Research Center TRR 109, Austrian
  Science Fund (FWF), grant No. I 02979-N35.\r\nWintraecken, Mathijs: Supported by
  the European Union’s Horizon 2020 research and innovation programme under the Marie
  Skłodowska-Curie grant agreement No. 754411, the Austrian science fund (FWF) grant
  No. M-3073, and the welcome package from IDEX of the Université Côte d'Azur."
alternative_title:
- LIPIcs
article_processing_charge: No
arxiv: 1
author:
- first_name: Dominique
  full_name: Attali, Dominique
  last_name: Attali
- first_name: Hana
  full_name: Kourimska, Hana
  id: D9B8E14C-3C26-11EA-98F5-1F833DDC885E
  last_name: Kourimska
  orcid: 0000-0001-7841-0091
- first_name: Christopher D
  full_name: Fillmore, Christopher D
  id: 35638A5C-AAC7-11E9-B0BF-5503E6697425
  last_name: Fillmore
- first_name: Ishika
  full_name: Ghosh, Ishika
  id: ee449b28-344d-11ef-a6d5-9ca430e9e9ff
  last_name: Ghosh
- first_name: André
  full_name: Lieutier, André
  last_name: Lieutier
- first_name: Elizabeth R
  full_name: Stephenson, Elizabeth R
  id: 2D04F932-F248-11E8-B48F-1D18A9856A87
  last_name: Stephenson
  orcid: 0000-0002-6862-208X
- first_name: Mathijs
  full_name: Wintraecken, Mathijs
  id: 307CFBC8-F248-11E8-B48F-1D18A9856A87
  last_name: Wintraecken
  orcid: 0000-0002-7472-2220
citation:
  ama: 'Attali D, Kourimska H, Fillmore CD, et al. Tight bounds for the learning of
    homotopy à la Niyogi, Smale, and Weinberger for subsets of euclidean spaces and
    of Riemannian manifolds. In: <i>40th International Symposium on Computational
    Geometry</i>. Vol 293. Schloss Dagstuhl - Leibniz-Zentrum für Informatik; 2024:11:1-11:19.
    doi:<a href="https://doi.org/10.4230/LIPIcs.SoCG.2024.11">10.4230/LIPIcs.SoCG.2024.11</a>'
  apa: 'Attali, D., Kourimska, H., Fillmore, C. D., Ghosh, I., Lieutier, A., Stephenson,
    E. R., &#38; Wintraecken, M. (2024). Tight bounds for the learning of homotopy
    à la Niyogi, Smale, and Weinberger for subsets of euclidean spaces and of Riemannian
    manifolds. In <i>40th International Symposium on Computational Geometry</i> (Vol.
    293, p. 11:1-11:19). Athens, Greece: Schloss Dagstuhl - Leibniz-Zentrum für Informatik.
    <a href="https://doi.org/10.4230/LIPIcs.SoCG.2024.11">https://doi.org/10.4230/LIPIcs.SoCG.2024.11</a>'
  chicago: Attali, Dominique, Hana Kourimska, Christopher D Fillmore, Ishika Ghosh,
    André Lieutier, Elizabeth R Stephenson, and Mathijs Wintraecken. “Tight Bounds
    for the Learning of Homotopy à La Niyogi, Smale, and Weinberger for Subsets of
    Euclidean Spaces and of Riemannian Manifolds.” In <i>40th International Symposium
    on Computational Geometry</i>, 293:11:1-11:19. Schloss Dagstuhl - Leibniz-Zentrum
    für Informatik, 2024. <a href="https://doi.org/10.4230/LIPIcs.SoCG.2024.11">https://doi.org/10.4230/LIPIcs.SoCG.2024.11</a>.
  ieee: D. Attali <i>et al.</i>, “Tight bounds for the learning of homotopy à la Niyogi,
    Smale, and Weinberger for subsets of euclidean spaces and of Riemannian manifolds,”
    in <i>40th International Symposium on Computational Geometry</i>, Athens, Greece,
    2024, vol. 293, p. 11:1-11:19.
  ista: 'Attali D, Kourimska H, Fillmore CD, Ghosh I, Lieutier A, Stephenson ER, Wintraecken
    M. 2024. Tight bounds for the learning of homotopy à la Niyogi, Smale, and Weinberger
    for subsets of euclidean spaces and of Riemannian manifolds. 40th International
    Symposium on Computational Geometry. SoCG: Symposium on Computational Geometry,
    LIPIcs, vol. 293, 11:1-11:19.'
  mla: Attali, Dominique, et al. “Tight Bounds for the Learning of Homotopy à La Niyogi,
    Smale, and Weinberger for Subsets of Euclidean Spaces and of Riemannian Manifolds.”
    <i>40th International Symposium on Computational Geometry</i>, vol. 293, Schloss
    Dagstuhl - Leibniz-Zentrum für Informatik, 2024, p. 11:1-11:19, doi:<a href="https://doi.org/10.4230/LIPIcs.SoCG.2024.11">10.4230/LIPIcs.SoCG.2024.11</a>.
  short: D. Attali, H. Kourimska, C.D. Fillmore, I. Ghosh, A. Lieutier, E.R. Stephenson,
    M. Wintraecken, in:, 40th International Symposium on Computational Geometry, Schloss
    Dagstuhl - Leibniz-Zentrum für Informatik, 2024, p. 11:1-11:19.
conference:
  end_date: 2024-06-14
  location: Athens, Greece
  name: 'SoCG: Symposium on Computational Geometry'
  start_date: 2024-06-11
date_created: 2024-06-25T11:45:58Z
date_published: 2024-06-06T00:00:00Z
date_updated: 2025-04-15T07:16:57Z
day: '06'
ddc:
- '516'
department:
- _id: GradSch
- _id: HeEd
doi: 10.4230/LIPIcs.SoCG.2024.11
ec_funded: 1
external_id:
  arxiv:
  - '2206.10485'
file:
- access_level: open_access
  checksum: 6a2ddc8b51aa58f197a8b294750f1f8d
  content_type: application/pdf
  creator: cfillmor
  date_created: 2024-06-25T11:47:26Z
  date_updated: 2024-06-25T11:47:26Z
  file_id: '17171'
  file_name: LIPIcs.SoCG.2024.11.pdf
  file_size: 20886142
  relation: main_file
  success: 1
file_date_updated: 2024-06-25T11:47:26Z
has_accepted_license: '1'
intvolume: '       293'
language:
- iso: eng
month: '06'
oa: 1
oa_version: Published Version
page: 11:1-11:19
project:
- _id: 266A2E9E-B435-11E9-9278-68D0E5697425
  call_identifier: H2020
  grant_number: '788183'
  name: Alpha Shape Theory Extended
- _id: 268116B8-B435-11E9-9278-68D0E5697425
  call_identifier: FWF
  grant_number: Z00342
  name: Mathematics, Computer Science
- _id: 260C2330-B435-11E9-9278-68D0E5697425
  call_identifier: H2020
  grant_number: '754411'
  name: ISTplus - Postdoctoral Fellowships
- _id: 2561EBF4-B435-11E9-9278-68D0E5697425
  call_identifier: FWF
  grant_number: I02979-N35
  name: Persistence and stability of geometric complexes
- _id: fc390959-9c52-11eb-aca3-afa58bd282b2
  grant_number: M03073
  name: Learning and triangulating manifolds via collapses
publication: 40th International Symposium on Computational Geometry
publication_identifier:
  eissn:
  - 1868-8969
  isbn:
  - '9783959773164'
publication_status: published
publisher: Schloss Dagstuhl - Leibniz-Zentrum für Informatik
quality_controlled: '1'
scopus_import: '1'
status: public
title: Tight bounds for the learning of homotopy à la Niyogi, Smale, and Weinberger
  for subsets of euclidean spaces and of Riemannian manifolds
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
volume: 293
year: '2024'
...
---
_id: '17190'
abstract:
- lang: eng
  text: "For a locally finite set, \U0001D434⊆ℝ\U0001D451\r\n, the \U0001D458\r\nth
    Brillouin zone of \U0001D44E∈\U0001D434\r\n is the region of points \U0001D465∈ℝ\U0001D451\r\n
    for which ‖\U0001D465−\U0001D44E‖\r\n is the \U0001D458\r\nth smallest among the
    Euclidean distances between \U0001D465\r\n and the points in \U0001D434\r\n. If
    \U0001D434\r\n is a lattice, the \U0001D458\r\nth Brillouin zones of the points
    in \U0001D434\r\n are translates of each other, and together they tile space.
    Depending on the value of \U0001D458\r\n, they express medium- or long-range order
    in the set. We study fundamental geometric and combinatorial properties of Brillouin
    zones, focusing on the integer lattice and its perturbations. Our results include
    the stability of a Brillouin zone under perturbations, a linear upper bound on
    the number of chambers in a zone for lattices in ℝ2\r\n, and the convergence of
    the maximum volume of a chamber to zero for the integer lattice."
acknowledgement: The second author is partially supported by the Alexander von Humboldt
  Foundation. The sixth author is supported by the European Union's Horizon 2020 research
  and innovation programme under Marie Sklodowska-Curie grant agreement 754411, and
  by Austrian Science Fund(FWF) grant M-3073. All other authors are supported by European
  Research Council (ERC) grant 788183, by the Wittgenstein Prize, by Austrian Science
  Fund (FWF) grant Z 342-N31, and by the DFG Collaborative Research Center TRR 109,
  Austrian Science Fund (FWF) grant I 02979-N35.
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: Herbert
  full_name: Edelsbrunner, Herbert
  id: 3FB178DA-F248-11E8-B48F-1D18A9856A87
  last_name: Edelsbrunner
  orcid: 0000-0002-9823-6833
- first_name: Alexey
  full_name: Garber, Alexey
  last_name: Garber
- first_name: Mohadese
  full_name: Ghafaris, Mohadese
  last_name: Ghafaris
- first_name: Teresa
  full_name: Heiss, Teresa
  id: 4879BB4E-F248-11E8-B48F-1D18A9856A87
  last_name: Heiss
  orcid: 0000-0002-1780-2689
- first_name: Morteza
  full_name: Saghafiant, Morteza
  last_name: Saghafiant
- first_name: Mathijs
  full_name: Wintraecken, Mathijs
  id: 307CFBC8-F248-11E8-B48F-1D18A9856A87
  last_name: Wintraecken
  orcid: 0000-0002-7472-2220
citation:
  ama: Edelsbrunner H, Garber A, Ghafaris M, Heiss T, Saghafiant M, Wintraecken M.
    Brillouin zones of integer lattices and their perturbations. <i>SIAM Journal on
    Discrete Mathematics</i>. 2024;38(2):1784-1807. doi:<a href="https://doi.org/10.1137/22M1489071">10.1137/22M1489071</a>
  apa: Edelsbrunner, H., Garber, A., Ghafaris, M., Heiss, T., Saghafiant, M., &#38;
    Wintraecken, M. (2024). Brillouin zones of integer lattices and their perturbations.
    <i>SIAM Journal on Discrete Mathematics</i>. Society for Industrial and Applied
    Mathematics. <a href="https://doi.org/10.1137/22M1489071">https://doi.org/10.1137/22M1489071</a>
  chicago: Edelsbrunner, Herbert, Alexey Garber, Mohadese Ghafaris, Teresa Heiss,
    Morteza Saghafiant, and Mathijs Wintraecken. “Brillouin Zones of Integer Lattices
    and Their Perturbations.” <i>SIAM Journal on Discrete Mathematics</i>. Society
    for Industrial and Applied Mathematics, 2024. <a href="https://doi.org/10.1137/22M1489071">https://doi.org/10.1137/22M1489071</a>.
  ieee: H. Edelsbrunner, A. Garber, M. Ghafaris, T. Heiss, M. Saghafiant, and M. Wintraecken,
    “Brillouin zones of integer lattices and their perturbations,” <i>SIAM Journal
    on Discrete Mathematics</i>, vol. 38, no. 2. Society for Industrial and Applied
    Mathematics, pp. 1784–1807, 2024.
  ista: Edelsbrunner H, Garber A, Ghafaris M, Heiss T, Saghafiant M, Wintraecken M.
    2024. Brillouin zones of integer lattices and their perturbations. SIAM Journal
    on Discrete Mathematics. 38(2), 1784–1807.
  mla: Edelsbrunner, Herbert, et al. “Brillouin Zones of Integer Lattices and Their
    Perturbations.” <i>SIAM Journal on Discrete Mathematics</i>, vol. 38, no. 2, Society
    for Industrial and Applied Mathematics, 2024, pp. 1784–807, doi:<a href="https://doi.org/10.1137/22M1489071">10.1137/22M1489071</a>.
  short: H. Edelsbrunner, A. Garber, M. Ghafaris, T. Heiss, M. Saghafiant, M. Wintraecken,
    SIAM Journal on Discrete Mathematics 38 (2024) 1784–1807.
corr_author: '1'
date_created: 2024-06-30T22:01:05Z
date_published: 2024-06-07T00:00:00Z
date_updated: 2025-09-08T08:06:04Z
day: '07'
department:
- _id: HeEd
doi: 10.1137/22M1489071
ec_funded: 1
external_id:
  arxiv:
  - '2204.01077'
  isi:
  - '001292728600001'
intvolume: '        38'
isi: 1
issue: '2'
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://doi.org/10.48550/arXiv.2204.01077
month: '06'
oa: 1
oa_version: Preprint
page: 1784-1807
project:
- _id: 260C2330-B435-11E9-9278-68D0E5697425
  call_identifier: H2020
  grant_number: '754411'
  name: ISTplus - Postdoctoral Fellowships
- _id: 266A2E9E-B435-11E9-9278-68D0E5697425
  call_identifier: H2020
  grant_number: '788183'
  name: Alpha Shape Theory Extended
- _id: fc390959-9c52-11eb-aca3-afa58bd282b2
  grant_number: M03073
  name: Learning and triangulating manifolds via collapses
- _id: 2561EBF4-B435-11E9-9278-68D0E5697425
  call_identifier: FWF
  grant_number: I02979-N35
  name: Persistence and stability of geometric complexes
- _id: 268116B8-B435-11E9-9278-68D0E5697425
  call_identifier: FWF
  grant_number: Z00342
  name: Mathematics, Computer Science
publication: SIAM Journal on Discrete Mathematics
publication_identifier:
  issn:
  - 0895-4801
publication_status: published
publisher: Society for Industrial and Applied Mathematics
quality_controlled: '1'
scopus_import: '1'
status: public
title: Brillouin zones of integer lattices and their perturbations
type: journal_article
user_id: 317138e5-6ab7-11ef-aa6d-ffef3953e345
volume: 38
year: '2024'
...
---
OA_place: publisher
OA_type: gold
_id: '18556'
abstract:
- lang: eng
  text: Given a finite set, A ⊆ ℝ², and a subset, B ⊆ A, the MST-ratio is the combined
    length of the minimum spanning trees of B and A⧵B divided by the length of the
    minimum spanning tree of A. The question of the supremum, over all sets A, of
    the maximum, over all subsets B, is related to the Steiner ratio, and we prove
    this sup-max is between 2.154 and 2.427. Restricting ourselves to 2-dimensional
    lattices, we prove that the sup-max is 2, while the inf-max is 1.25. By some margin
    the most difficult of these results is the upper bound for the inf-max, which
    we prove by showing that the hexagonal lattice cannot have MST-ratio larger than
    1.25.
acknowledgement: This project has received funding from the European Research Council
  (ERC) under the European Union’s Horizon 2020 research and innovation programme,
  grant no. 788183, from the Wittgenstein Prize, Austrian Science Fund (FWF), grant
  no. Z 342-N31, and from the DFG Collaborative Research Center TRR 109, "Discretization
  in Geometry and Dynamics", Austrian Science Fund (FWF), grant no. I 02979-N35.
alternative_title:
- LIPIcs
article_number: '3'
article_processing_charge: Yes
arxiv: 1
author:
- first_name: Sebastiano
  full_name: Cultrera di Montesano, Sebastiano
  id: 34D2A09C-F248-11E8-B48F-1D18A9856A87
  last_name: Cultrera di Montesano
  orcid: 0000-0001-6249-0832
- first_name: Ondrej
  full_name: Draganov, Ondrej
  id: 2B23F01E-F248-11E8-B48F-1D18A9856A87
  last_name: Draganov
  orcid: 0000-0003-0464-3823
- first_name: Herbert
  full_name: Edelsbrunner, Herbert
  id: 3FB178DA-F248-11E8-B48F-1D18A9856A87
  last_name: Edelsbrunner
  orcid: 0000-0002-9823-6833
- first_name: Morteza
  full_name: Saghafian, Morteza
  id: f86f7148-b140-11ec-9577-95435b8df824
  last_name: Saghafian
citation:
  ama: 'Cultrera di Montesano S, Draganov O, Edelsbrunner H, Saghafian M. The Euclidean
    MST-ratio for bi-colored lattices. In: <i>32nd International Symposium on Graph
    Drawing and Network Visualization</i>. Vol 320. Schloss Dagstuhl - Leibniz-Zentrum
    für Informatik; 2024. doi:<a href="https://doi.org/10.4230/LIPIcs.GD.2024.3">10.4230/LIPIcs.GD.2024.3</a>'
  apa: 'Cultrera di Montesano, S., Draganov, O., Edelsbrunner, H., &#38; Saghafian,
    M. (2024). The Euclidean MST-ratio for bi-colored lattices. In <i>32nd International
    Symposium on Graph Drawing and Network Visualization</i> (Vol. 320). Vienna, Austria:
    Schloss Dagstuhl - Leibniz-Zentrum für Informatik. <a href="https://doi.org/10.4230/LIPIcs.GD.2024.3">https://doi.org/10.4230/LIPIcs.GD.2024.3</a>'
  chicago: Cultrera di Montesano, Sebastiano, Ondrej Draganov, Herbert Edelsbrunner,
    and Morteza Saghafian. “The Euclidean MST-Ratio for Bi-Colored Lattices.” In <i>32nd
    International Symposium on Graph Drawing and Network Visualization</i>, Vol. 320.
    Schloss Dagstuhl - Leibniz-Zentrum für Informatik, 2024. <a href="https://doi.org/10.4230/LIPIcs.GD.2024.3">https://doi.org/10.4230/LIPIcs.GD.2024.3</a>.
  ieee: S. Cultrera di Montesano, O. Draganov, H. Edelsbrunner, and M. Saghafian,
    “The Euclidean MST-ratio for bi-colored lattices,” in <i>32nd International Symposium
    on Graph Drawing and Network Visualization</i>, Vienna, Austria, 2024, vol. 320.
  ista: 'Cultrera di Montesano S, Draganov O, Edelsbrunner H, Saghafian M. 2024. The
    Euclidean MST-ratio for bi-colored lattices. 32nd International Symposium on Graph
    Drawing and Network Visualization. GD: Graph Drawing and Network Visualization,
    LIPIcs, vol. 320, 3.'
  mla: Cultrera di Montesano, Sebastiano, et al. “The Euclidean MST-Ratio for Bi-Colored
    Lattices.” <i>32nd International Symposium on Graph Drawing and Network Visualization</i>,
    vol. 320, 3, Schloss Dagstuhl - Leibniz-Zentrum für Informatik, 2024, doi:<a href="https://doi.org/10.4230/LIPIcs.GD.2024.3">10.4230/LIPIcs.GD.2024.3</a>.
  short: S. Cultrera di Montesano, O. Draganov, H. Edelsbrunner, M. Saghafian, in:,
    32nd International Symposium on Graph Drawing and Network Visualization, Schloss
    Dagstuhl - Leibniz-Zentrum für Informatik, 2024.
conference:
  end_date: 2024-09-20
  location: Vienna, Austria
  name: 'GD: Graph Drawing and Network Visualization'
  start_date: 2024-09-18
corr_author: '1'
date_created: 2024-11-17T23:01:47Z
date_published: 2024-10-28T00:00:00Z
date_updated: 2025-12-02T13:50:50Z
day: '28'
ddc:
- '510'
department:
- _id: HeEd
doi: 10.4230/LIPIcs.GD.2024.3
ec_funded: 1
external_id:
  arxiv:
  - '2403.10204'
  isi:
  - '001540278400001'
file:
- access_level: open_access
  checksum: 5f9b35e115c3d375e99be78da9054cb4
  content_type: application/pdf
  creator: dernst
  date_created: 2024-11-18T07:49:25Z
  date_updated: 2024-11-18T07:49:25Z
  file_id: '18560'
  file_name: 2024_LIPIcs_CultreradiMontesano.pdf
  file_size: 908541
  relation: main_file
  success: 1
file_date_updated: 2024-11-18T07:49:25Z
has_accepted_license: '1'
intvolume: '       320'
isi: 1
language:
- iso: eng
month: '10'
oa: 1
oa_version: Published Version
project:
- _id: 266A2E9E-B435-11E9-9278-68D0E5697425
  call_identifier: H2020
  grant_number: '788183'
  name: Alpha Shape Theory Extended
- _id: 268116B8-B435-11E9-9278-68D0E5697425
  call_identifier: FWF
  grant_number: Z00342
  name: Mathematics, Computer Science
- _id: 2561EBF4-B435-11E9-9278-68D0E5697425
  call_identifier: FWF
  grant_number: I02979-N35
  name: Persistence and stability of geometric complexes
publication: 32nd International Symposium on Graph Drawing and Network Visualization
publication_identifier:
  isbn:
  - '9783959773430'
  issn:
  - 1868-8969
publication_status: published
publisher: Schloss Dagstuhl - Leibniz-Zentrum für Informatik
quality_controlled: '1'
scopus_import: '1'
status: public
title: The Euclidean MST-ratio for bi-colored lattices
tmp:
  image: /images/cc_by.png
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  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
volume: 320
year: '2024'
...
---
DOAJ_listed: '1'
OA_place: publisher
OA_type: gold
_id: '18604'
abstract:
- lang: eng
  text: 'A face in a curve arrangement is called popular if it is bounded by the same
    curve multiple times. Motivated by the automatic generation of curved nonogram
    puzzles, we investigate possibilities to eliminate the popular faces in an arrangement
    by inserting a single additional curve. This turns out to be NP-hard; however,
    it becomes tractable when the number of popular faces is small: We present a randomized
    FPT-time algorithm where the parameter is the number of popular faces.'
acknowledgement: "This work was initiated at the 16th European Research Week on Geometric
  Graphs in Strobl in 2019. A.W. has been supported by the Austrian Science Fund (FWF):
  W1230. S.T. has been funded by the Vienna Science and Technology Fund (WWTF) [10.47379/ICT19035]
  and by the NWO Gravitation project NETWORKS under grant no. 024.002.003. Part of
  the work was done while A.W. was emplyed at Graz University of Technology. Preliminary
  versions of this work have been presented at the 38th European Workshop on Computational
  Geometry (EuroCG\r\n2022) in Perugia [10] and at the 31st International Symposium
  on Graph Drawing and Network Visualization (GD 2023) in Isola delle Femmine [11]."
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: Phoebe
  full_name: De Nooijer, Phoebe
  last_name: De Nooijer
- first_name: Soeren
  full_name: Terziadis, Soeren
  last_name: Terziadis
- first_name: Alexandra
  full_name: Weinberger, Alexandra
  last_name: Weinberger
- first_name: Zuzana
  full_name: Masárová, Zuzana
  id: 45CFE238-F248-11E8-B48F-1D18A9856A87
  last_name: Masárová
  orcid: 0000-0002-6660-1322
- first_name: Tamara
  full_name: Mchedlidze, Tamara
  last_name: Mchedlidze
- first_name: Maarten
  full_name: Löffler, Maarten
  last_name: Löffler
- first_name: Günter
  full_name: Rote, Günter
  last_name: Rote
citation:
  ama: De Nooijer P, Terziadis S, Weinberger A, et al. Removing popular faces in curve
    arrangements. <i>Journal of Graph Algorithms and Applications</i>. 2024;28(2):47-82.
    doi:<a href="https://doi.org/10.7155/jgaa.v28i2.2988">10.7155/jgaa.v28i2.2988</a>
  apa: De Nooijer, P., Terziadis, S., Weinberger, A., Masárová, Z., Mchedlidze, T.,
    Löffler, M., &#38; Rote, G. (2024). Removing popular faces in curve arrangements.
    <i>Journal of Graph Algorithms and Applications</i>. Brown University. <a href="https://doi.org/10.7155/jgaa.v28i2.2988">https://doi.org/10.7155/jgaa.v28i2.2988</a>
  chicago: De Nooijer, Phoebe, Soeren Terziadis, Alexandra Weinberger, Zuzana Masárová,
    Tamara Mchedlidze, Maarten Löffler, and Günter Rote. “Removing Popular Faces in
    Curve Arrangements.” <i>Journal of Graph Algorithms and Applications</i>. Brown
    University, 2024. <a href="https://doi.org/10.7155/jgaa.v28i2.2988">https://doi.org/10.7155/jgaa.v28i2.2988</a>.
  ieee: P. De Nooijer <i>et al.</i>, “Removing popular faces in curve arrangements,”
    <i>Journal of Graph Algorithms and Applications</i>, vol. 28, no. 2. Brown University,
    pp. 47–82, 2024.
  ista: De Nooijer P, Terziadis S, Weinberger A, Masárová Z, Mchedlidze T, Löffler
    M, Rote G. 2024. Removing popular faces in curve arrangements. Journal of Graph
    Algorithms and Applications. 28(2), 47–82.
  mla: De Nooijer, Phoebe, et al. “Removing Popular Faces in Curve Arrangements.”
    <i>Journal of Graph Algorithms and Applications</i>, vol. 28, no. 2, Brown University,
    2024, pp. 47–82, doi:<a href="https://doi.org/10.7155/jgaa.v28i2.2988">10.7155/jgaa.v28i2.2988</a>.
  short: P. De Nooijer, S. Terziadis, A. Weinberger, Z. Masárová, T. Mchedlidze, M.
    Löffler, G. Rote, Journal of Graph Algorithms and Applications 28 (2024) 47–82.
corr_author: '1'
date_created: 2024-12-01T23:01:54Z
date_published: 2024-11-03T00:00:00Z
date_updated: 2024-12-03T09:49:18Z
day: '03'
ddc:
- '510'
department:
- _id: UlWa
- _id: HeEd
doi: 10.7155/jgaa.v28i2.2988
external_id:
  arxiv:
  - '2202.12175'
file:
- access_level: open_access
  checksum: be611da6f9d790dc980d6fb7283fe889
  content_type: application/pdf
  creator: dernst
  date_created: 2024-12-03T09:45:00Z
  date_updated: 2024-12-03T09:45:00Z
  file_id: '18609'
  file_name: 2024_JourGraphAlgorithms_deNooijer.pdf
  file_size: 1582493
  relation: main_file
  success: 1
file_date_updated: 2024-12-03T09:45:00Z
has_accepted_license: '1'
intvolume: '        28'
issue: '2'
language:
- iso: eng
month: '11'
oa: 1
oa_version: Published Version
page: 47-82
publication: Journal of Graph Algorithms and Applications
publication_identifier:
  issn:
  - 1526-1719
publication_status: published
publisher: Brown University
quality_controlled: '1'
scopus_import: '1'
status: public
title: Removing popular faces in curve arrangements
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: 28
year: '2024'
...
---
OA_place: publisher
_id: '18667'
abstract:
- lang: eng
  text: "Many chemical and physical properties of materials are determined by the
    material’s shape,\r\nfor example the size of its pores and the width of its tunnels.
    This makes materials science\r\na prime application area for geometrical and topological
    methods. Nevertheless many\r\nmethods in topological data analysis have not been
    satisfyingly extended to the needs of\r\nmaterials science. This thesis provides
    new methods and new mathematical theorems\r\ntargeted at those specific needs
    by answering four different research questions. While the\r\nmotivation for each
    of the research questions arises from materials science, the methods\r\nare versatile
    and can be applied in different areas as well. \r\n\r\nThe first research question
    is concerned with image data, for example a three-dimensional\r\ncomputed tomography
    (CT) scan of a material, like sand or stone. There are two commonly\r\nused topologies
    for digital images and depending on the application either of them might be\r\nrequired.
    However, software for computing the topological data analysis method persistence\r\nhomology,
    usually supports only one of the two topologies. We answer the question how to\r\ncompute
    persistent homology of an image with respect to one of the two topologies using\r\nsoftware
    that is intended for the other topology. \r\n\r\nThe second research question
    is concerned with image data as well, and asks how much\r\nof the topological
    information of an image is lost when the resolution is coarsened. As\r\ncomputer
    tomography scanners are more expensive the higher the resolution, it is an\r\nimportant
    question in materials science to know which resolution is enough to get satisfying\r\npersistent
    homology. We give theoretical bounds on the information loss based on different\r\ngeometrical
    properties of the object to be scanned. In addition, we conduct experiments on\r\nsand
    and stone CT image data. \r\n\r\nThe third research question is motivated by comparing
    crystalline materials efficiently. As\r\nthe atoms within a crystal repeat periodically,
    crystalline materials are either modeled by\r\nunmanageable infinite periodic
    point sets, or by one of their fundamental domains, which is\r\nunstable under
    perturbation. Therefore a fingerprint of crystalline materials is needed, with\r\nappropriate
    properties such that comparing the crystals can be eased by comparing the\r\nfingerprints
    instead. We define the density fingerprint and prove the necessary properties.
    \r\n\r\nThe fourth research question is motivated by studying the hole-structure
    or connectedness,\r\ni.e. persistent homology or merge trees, of crystalline materials.
    A common way to deal\r\nwith periodicity is to take a fundamental domain and identify
    opposite boundaries to form a\r\ntorus. However, computing persistent homology
    or merge trees on that torus loses some\r\nof the information materials scientists
    are interested in and is additionally not stable under\r\ncertain noise. We therefore
    decorate the merge tree stemming from the torus with additional\r\ninformation
    describing the density and growth rate of the periodic copies of a component\r\nwithin
    a growing spherical window. We prove all desired properties, like stability and
    efficient\r\ncomputability."
acknowledgement: "I was supported by the European Research Council (ERC) Horizon 2020
  project\r\n“Alpha Shape Theory Extended” No. 788183 and by the Pöttinger Scholarship.
  In addition,\r\nI am very thankful for having been able to attend the second Workshop
  for Women in\r\nComputational Topology in July 2019, funded by the Mathematical
  Sciences Institute at\r\nANU, the US National Science Foundation through the award
  CCF-1841455, the Australian\r\nMathematical Sciences Institute and the Association
  for Women in Mathematics. Two of the\r\nprojects presented in this thesis started
  there. One of them reached completion thanks to\r\nfunding from the MSRI Summer
  Research in Mathematics program awarded to me and my\r\ncollaborators in 2020."
alternative_title:
- ISTA Thesis
article_processing_charge: No
author:
- first_name: Teresa
  full_name: Heiss, Teresa
  id: 4879BB4E-F248-11E8-B48F-1D18A9856A87
  last_name: Heiss
  orcid: 0000-0002-1780-2689
citation:
  ama: Heiss T. New methods for applying topological data analysis to materials science.
    2024. doi:<a href="https://doi.org/10.15479/at:ista:18667">10.15479/at:ista:18667</a>
  apa: Heiss, T. (2024). <i>New methods for applying topological data analysis to
    materials science</i>. Institute of Science and Technology Austria. <a href="https://doi.org/10.15479/at:ista:18667">https://doi.org/10.15479/at:ista:18667</a>
  chicago: Heiss, Teresa. “New Methods for Applying Topological Data Analysis to Materials
    Science.” Institute of Science and Technology Austria, 2024. <a href="https://doi.org/10.15479/at:ista:18667">https://doi.org/10.15479/at:ista:18667</a>.
  ieee: T. Heiss, “New methods for applying topological data analysis to materials
    science,” Institute of Science and Technology Austria, 2024.
  ista: Heiss T. 2024. New methods for applying topological data analysis to materials
    science. Institute of Science and Technology Austria.
  mla: Heiss, Teresa. <i>New Methods for Applying Topological Data Analysis to Materials
    Science</i>. Institute of Science and Technology Austria, 2024, doi:<a href="https://doi.org/10.15479/at:ista:18667">10.15479/at:ista:18667</a>.
  short: T. Heiss, New Methods for Applying Topological Data Analysis to Materials
    Science, Institute of Science and Technology Austria, 2024.
corr_author: '1'
date_created: 2024-12-17T16:17:55Z
date_published: 2024-12-17T00:00:00Z
date_updated: 2026-04-07T12:54:10Z
day: '17'
ddc:
- '514'
- '516'
- '004'
degree_awarded: PhD
department:
- _id: GradSch
- _id: HeEd
doi: 10.15479/at:ista:18667
ec_funded: 1
file:
- access_level: open_access
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  creator: theiss
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  date_created: 2024-12-19T10:24:50Z
  date_updated: 2024-12-19T10:24:50Z
  file_id: '18687'
  file_name: PhD_Thesis.zip
  file_size: 17197731
  relation: source_file
file_date_updated: 2024-12-19T10:24:50Z
has_accepted_license: '1'
keyword:
- persistent homology
- topological data analysis
- periodic
- crystalline materials
- images
- fingerprint
language:
- iso: eng
month: '12'
oa: 1
oa_version: Published Version
page: '111'
project:
- _id: 266A2E9E-B435-11E9-9278-68D0E5697425
  call_identifier: H2020
  grant_number: '788183'
  name: Alpha Shape Theory Extended
publication_identifier:
  isbn:
  - 978-3-99078-052-7
  issn:
  - 2663-337X
publication_status: published
publisher: Institute of Science and Technology Austria
related_material:
  record:
  - id: '10828'
    relation: part_of_dissertation
    status: public
  - id: '11440'
    relation: part_of_dissertation
    status: public
  - id: '18673'
    relation: part_of_dissertation
    status: public
  - id: '9345'
    relation: part_of_dissertation
    status: public
status: public
supervisor:
- first_name: Herbert
  full_name: Edelsbrunner, Herbert
  id: 3FB178DA-F248-11E8-B48F-1D18A9856A87
  last_name: Edelsbrunner
  orcid: 0000-0002-9823-6833
title: New methods for applying topological data analysis to materials science
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: dissertation
user_id: ba8df636-2132-11f1-aed0-ed93e2281fdd
year: '2024'
...
---
OA_place: repository
_id: '18673'
abstract:
- lang: eng
  text: "Motivated by applications to crystalline materials, we generalize the merge
    tree and the related barcode of a filtered complex to the periodic setting in
    Euclidean space. They are invariant under isometries, changing bases, and indeed
    changing lattices. In addition, we prove stability under perturbations and provide
    an algorithm that under mild geometric conditions typically satisfied by crystalline
    materials takes O((n+m)logn) time, in which n and m are the numbers of vertices
    and edges in the quotient complex, respectively.\r\n"
acknowledgement: "Both authors are partially supported by the European Research Council
  (ERC) Horizon 2020 project\r\n‘Alpha Shape Theory Extended’, grant no. 788183. The
  first author is also partially supported by the DFG\r\nCollaborative Research Center
  TRR 109, ‘Discretization in Geometry and Dynamics’, Austrian Science Fund\r\n(FWF),
  grant no. I 02979-N35."
article_processing_charge: No
arxiv: 1
author:
- first_name: Herbert
  full_name: Edelsbrunner, Herbert
  id: 3FB178DA-F248-11E8-B48F-1D18A9856A87
  last_name: Edelsbrunner
  orcid: 0000-0002-9823-6833
- first_name: Teresa
  full_name: Heiss, Teresa
  id: 4879BB4E-F248-11E8-B48F-1D18A9856A87
  last_name: Heiss
  orcid: 0000-0002-1780-2689
citation:
  ama: Edelsbrunner H, Heiss T. Merge trees of periodic filtrations. <i>arXiv</i>.
    doi:<a href="https://doi.org/10.48550/arXiv.2408.16575">10.48550/arXiv.2408.16575</a>
  apa: Edelsbrunner, H., &#38; Heiss, T. (n.d.). Merge trees of periodic filtrations.
    <i>arXiv</i>. <a href="https://doi.org/10.48550/arXiv.2408.16575">https://doi.org/10.48550/arXiv.2408.16575</a>
  chicago: Edelsbrunner, Herbert, and Teresa Heiss. “Merge Trees of Periodic Filtrations.”
    <i>ArXiv</i>, n.d. <a href="https://doi.org/10.48550/arXiv.2408.16575">https://doi.org/10.48550/arXiv.2408.16575</a>.
  ieee: H. Edelsbrunner and T. Heiss, “Merge trees of periodic filtrations,” <i>arXiv</i>.
    .
  ista: Edelsbrunner H, Heiss T. Merge trees of periodic filtrations. arXiv, <a href="https://doi.org/10.48550/arXiv.2408.16575">10.48550/arXiv.2408.16575</a>.
  mla: Edelsbrunner, Herbert, and Teresa Heiss. “Merge Trees of Periodic Filtrations.”
    <i>ArXiv</i>, doi:<a href="https://doi.org/10.48550/arXiv.2408.16575">10.48550/arXiv.2408.16575</a>.
  short: H. Edelsbrunner, T. Heiss, ArXiv (n.d.).
corr_author: '1'
date_created: 2024-12-18T14:06:57Z
date_published: 2024-08-29T00:00:00Z
date_updated: 2026-04-07T12:54:09Z
day: '29'
department:
- _id: HeEd
doi: 10.48550/arXiv.2408.16575
ec_funded: 1
external_id:
  arxiv:
  - '2408.16575'
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://doi.org/10.48550/arXiv.2408.16575
month: '08'
oa: 1
oa_version: Preprint
project:
- _id: 266A2E9E-B435-11E9-9278-68D0E5697425
  call_identifier: H2020
  grant_number: '788183'
  name: Alpha Shape Theory Extended
- _id: 2561EBF4-B435-11E9-9278-68D0E5697425
  call_identifier: FWF
  grant_number: I02979-N35
  name: Persistence and stability of geometric complexes
publication: arXiv
publication_status: draft
related_material:
  record:
  - id: '18667'
    relation: dissertation_contains
    status: public
status: public
title: Merge trees of periodic filtrations
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: preprint
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
year: '2024'
...
---
OA_place: repository
_id: '18981'
abstract:
- lang: eng
  text: We establish several results combining discrete Morse theory and microlocal
    sheaf theory in the setting of finite posets and simplicial complexes. Our primary
    tool is a computationally tractable description of the bounded derived category
    of sheaves on a poset with the Alexandrov topology. We prove that each bounded
    complex of sheaves on a finite poset admits a unique (up to isomorphism of complexes)
    minimal injective resolution, and we provide algorithms for computing minimal
    injective resolution of an injective complex, as well as several useful functors
    between derived categories of sheaves. For the constant sheaf on a simplicial
    complex, we give asymptotically tight bounds on the complexity of computing the
    minimal injective resolution using those algorithms. Our main result is a novel
    definition of the discrete microsupport of a bounded complex of sheaves on a finite
    poset. We detail several foundational properties of the discrete microsupport,
    as well as a microlocal generalization of the discrete homological Morse theorem
    and Morse inequalities.
acknowledgement: "This project has received funding from the European Research Council
  (ERC) under the European\r\nUnion’s Horizon 2020 research and innovation programme,
  grant no. 788183, from the Wittgenstein Prize,\r\nAustrian Science Fund (FWF), grant
  no. Z 342-N31, and from the DFG Collaborative Research Center TRR\r\n109, ‘Discretization
  in Geometry and Dynamics’, Austrian Science Fund (FWF), grant no. I 02979-N35."
article_processing_charge: No
arxiv: 1
author:
- first_name: Adam
  full_name: Brown, Adam
  last_name: Brown
- first_name: Ondrej
  full_name: Draganov, Ondrej
  id: 2B23F01E-F248-11E8-B48F-1D18A9856A87
  last_name: Draganov
  orcid: 0000-0003-0464-3823
citation:
  ama: Brown A, Draganov O. Discrete microlocal Morse theory. <i>arXiv</i>. doi:<a
    href="https://doi.org/10.48550/arXiv.2209.14993">10.48550/arXiv.2209.14993</a>
  apa: Brown, A., &#38; Draganov, O. (n.d.). Discrete microlocal Morse theory. <i>arXiv</i>.
    <a href="https://doi.org/10.48550/arXiv.2209.14993">https://doi.org/10.48550/arXiv.2209.14993</a>
  chicago: Brown, Adam, and Ondrej Draganov. “Discrete Microlocal Morse Theory.” <i>ArXiv</i>,
    n.d. <a href="https://doi.org/10.48550/arXiv.2209.14993">https://doi.org/10.48550/arXiv.2209.14993</a>.
  ieee: A. Brown and O. Draganov, “Discrete microlocal Morse theory,” <i>arXiv</i>.
    .
  ista: Brown A, Draganov O. Discrete microlocal Morse theory. arXiv, <a href="https://doi.org/10.48550/arXiv.2209.14993">10.48550/arXiv.2209.14993</a>.
  mla: Brown, Adam, and Ondrej Draganov. “Discrete Microlocal Morse Theory.” <i>ArXiv</i>,
    doi:<a href="https://doi.org/10.48550/arXiv.2209.14993">10.48550/arXiv.2209.14993</a>.
  short: A. Brown, O. Draganov, ArXiv (n.d.).
corr_author: '1'
date_created: 2025-01-31T17:03:04Z
date_published: 2024-06-09T00:00:00Z
date_updated: 2026-04-07T11:47:29Z
day: '09'
department:
- _id: HeEd
doi: 10.48550/arXiv.2209.14993
ec_funded: 1
external_id:
  arxiv:
  - '2209.14993'
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://doi.org/10.48550/arXiv.2209.14993
month: '06'
oa: 1
oa_version: Preprint
project:
- _id: 266A2E9E-B435-11E9-9278-68D0E5697425
  call_identifier: H2020
  grant_number: '788183'
  name: Alpha Shape Theory Extended
- _id: 268116B8-B435-11E9-9278-68D0E5697425
  call_identifier: FWF
  grant_number: Z00342
  name: Mathematics, Computer Science
- _id: 2561EBF4-B435-11E9-9278-68D0E5697425
  call_identifier: FWF
  grant_number: I02979-N35
  name: Persistence and stability of geometric complexes
publication: arXiv
publication_status: draft
related_material:
  record:
  - id: '20323'
    relation: later_version
    status: public
  - id: '18979'
    relation: dissertation_contains
    status: public
status: public
title: Discrete microlocal Morse theory
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: preprint
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
year: '2024'
...
---
OA_place: publisher
OA_type: gold
_id: '18998'
abstract:
- lang: eng
  text: Word embeddings represent language vocabularies as clouds of d-dimensional
    points. We investigate how information is conveyed by the general shape of these
    clouds, instead of representing the semantic meaning of each token. Specifically,
    we use the notion of persistent homology from topological data analysis (TDA)
    to measure the distances between language pairs from the shape of their unlabeled
    embeddings. These distances quantify the degree of non-isometry of the embeddings.
    To distinguish whether these differences are random training errors or capture
    real information about the languages, we use the computed distance matrices to
    construct language phylogenetic trees over 81 Indo-European languages. Careful
    evaluation shows that our reconstructed trees exhibit strong and statistically-significant
    similarities to the reference.
article_processing_charge: No
arxiv: 1
author:
- first_name: Ondrej
  full_name: Draganov, Ondrej
  id: 2B23F01E-F248-11E8-B48F-1D18A9856A87
  last_name: Draganov
  orcid: 0000-0003-0464-3823
- first_name: Steven
  full_name: Skiena, Steven
  last_name: Skiena
citation:
  ama: 'Draganov O, Skiena S. The shape of word embeddings: Quantifying non-isometry
    with topological data analysis. In: <i>Findings of the Association for Computational
    Linguistics: EMNLP 2024</i>. Association for Computational Linguistics; 2024:12080-12099.
    doi:<a href="https://doi.org/10.18653/v1/2024.findings-emnlp.705">10.18653/v1/2024.findings-emnlp.705</a>'
  apa: 'Draganov, O., &#38; Skiena, S. (2024). The shape of word embeddings: Quantifying
    non-isometry with topological data analysis. In <i>Findings of the Association
    for Computational Linguistics: EMNLP 2024</i> (pp. 12080–12099). Miami, FL, United
    States: Association for Computational Linguistics. <a href="https://doi.org/10.18653/v1/2024.findings-emnlp.705">https://doi.org/10.18653/v1/2024.findings-emnlp.705</a>'
  chicago: 'Draganov, Ondrej, and Steven Skiena. “The Shape of Word Embeddings: Quantifying
    Non-Isometry with Topological Data Analysis.” In <i>Findings of the Association
    for Computational Linguistics: EMNLP 2024</i>, 12080–99. Association for Computational
    Linguistics, 2024. <a href="https://doi.org/10.18653/v1/2024.findings-emnlp.705">https://doi.org/10.18653/v1/2024.findings-emnlp.705</a>.'
  ieee: 'O. Draganov and S. Skiena, “The shape of word embeddings: Quantifying non-isometry
    with topological data analysis,” in <i>Findings of the Association for Computational
    Linguistics: EMNLP 2024</i>, Miami, FL, United States, 2024, pp. 12080–12099.'
  ista: 'Draganov O, Skiena S. 2024. The shape of word embeddings: Quantifying non-isometry
    with topological data analysis. Findings of the Association for Computational
    Linguistics: EMNLP 2024. EMNLP: Conference on Empirical Methods in Natural Language
    Processing, 12080–12099.'
  mla: 'Draganov, Ondrej, and Steven Skiena. “The Shape of Word Embeddings: Quantifying
    Non-Isometry with Topological Data Analysis.” <i>Findings of the Association for
    Computational Linguistics: EMNLP 2024</i>, Association for Computational Linguistics,
    2024, pp. 12080–99, doi:<a href="https://doi.org/10.18653/v1/2024.findings-emnlp.705">10.18653/v1/2024.findings-emnlp.705</a>.'
  short: 'O. Draganov, S. Skiena, in:, Findings of the Association for Computational
    Linguistics: EMNLP 2024, Association for Computational Linguistics, 2024, pp.
    12080–12099.'
conference:
  end_date: 2024-11-16
  location: Miami, FL, United States
  name: 'EMNLP: Conference on Empirical Methods in Natural Language Processing'
  start_date: 2024-11-12
corr_author: '1'
date_created: 2025-02-04T16:19:28Z
date_published: 2024-11-01T00:00:00Z
date_updated: 2025-02-10T08:21:37Z
day: '01'
ddc:
- '500'
department:
- _id: GradSch
- _id: HeEd
doi: 10.18653/v1/2024.findings-emnlp.705
external_id:
  arxiv:
  - '2404.00500'
file:
- access_level: open_access
  checksum: f4416a5962194f0181ab0dc7f9ef93c0
  content_type: application/pdf
  creator: dernst
  date_created: 2025-02-10T08:20:34Z
  date_updated: 2025-02-10T08:20:34Z
  file_id: '19016'
  file_name: 2024_EMNLP_Draganov.pdf
  file_size: 1312638
  relation: main_file
  success: 1
file_date_updated: 2025-02-10T08:20:34Z
has_accepted_license: '1'
language:
- iso: eng
month: '11'
oa: 1
oa_version: Published Version
page: 12080-12099
publication: 'Findings of the Association for Computational Linguistics: EMNLP 2024'
publication_status: published
publisher: Association for Computational Linguistics
quality_controlled: '1'
scopus_import: '1'
status: public
title: 'The shape of word embeddings: Quantifying non-isometry with topological data
  analysis'
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: '2024'
...
---
OA_place: repository
OA_type: green
_id: '18999'
abstract:
- lang: eng
  text: Exploring the shape of point configurations has been a key driver in the evolution
    of TDA (short for topological data analysis) since its infancy. This survey illustrates
    the recent efforts to broaden these ideas to model spatial interactions among
    multiple configurations, each distinguished by a color. It describes advances
    in this area and prepares the ground for further exploration by mentioning unresolved
    questions and promising research avenues while focusing on the overlap with discrete
    geometry.
article_number: '2406.04102'
article_processing_charge: No
arxiv: 1
author:
- first_name: Sebastiano
  full_name: Cultrera di Montesano, Sebastiano
  id: 34D2A09C-F248-11E8-B48F-1D18A9856A87
  last_name: Cultrera di Montesano
  orcid: 0000-0001-6249-0832
- first_name: Ondrej
  full_name: Draganov, Ondrej
  id: 2B23F01E-F248-11E8-B48F-1D18A9856A87
  last_name: Draganov
  orcid: 0000-0003-0464-3823
- first_name: Herbert
  full_name: Edelsbrunner, Herbert
  id: 3FB178DA-F248-11E8-B48F-1D18A9856A87
  last_name: Edelsbrunner
  orcid: 0000-0002-9823-6833
- first_name: Morteza
  full_name: Saghafian, Morteza
  id: f86f7148-b140-11ec-9577-95435b8df824
  last_name: Saghafian
citation:
  ama: Cultrera di Montesano S, Draganov O, Edelsbrunner H, Saghafian M. Chromatic
    topological data analysis. <i>arXiv</i>. doi:<a href="https://doi.org/10.48550/ARXIV.2406.04102">10.48550/ARXIV.2406.04102</a>
  apa: Cultrera di Montesano, S., Draganov, O., Edelsbrunner, H., &#38; Saghafian,
    M. (n.d.). Chromatic topological data analysis. <i>arXiv</i>. <a href="https://doi.org/10.48550/ARXIV.2406.04102">https://doi.org/10.48550/ARXIV.2406.04102</a>
  chicago: Cultrera di Montesano, Sebastiano, Ondrej Draganov, Herbert Edelsbrunner,
    and Morteza Saghafian. “Chromatic Topological Data Analysis.” <i>ArXiv</i>, n.d.
    <a href="https://doi.org/10.48550/ARXIV.2406.04102">https://doi.org/10.48550/ARXIV.2406.04102</a>.
  ieee: S. Cultrera di Montesano, O. Draganov, H. Edelsbrunner, and M. Saghafian,
    “Chromatic topological data analysis,” <i>arXiv</i>. .
  ista: Cultrera di Montesano S, Draganov O, Edelsbrunner H, Saghafian M. Chromatic
    topological data analysis. arXiv, 2406.04102.
  mla: Cultrera di Montesano, Sebastiano, et al. “Chromatic Topological Data Analysis.”
    <i>ArXiv</i>, 2406.04102, doi:<a href="https://doi.org/10.48550/ARXIV.2406.04102">10.48550/ARXIV.2406.04102</a>.
  short: S. Cultrera di Montesano, O. Draganov, H. Edelsbrunner, M. Saghafian, ArXiv
    (n.d.).
corr_author: '1'
date_created: 2025-02-04T16:21:21Z
date_published: 2024-06-06T00:00:00Z
date_updated: 2025-02-10T08:14:27Z
day: '06'
ddc:
- '510'
department:
- _id: GradSch
- _id: HeEd
doi: 10.48550/ARXIV.2406.04102
external_id:
  arxiv:
  - '2406.04102'
has_accepted_license: '1'
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://doi.org/10.48550/arXiv.2406.04102
month: '06'
oa: 1
oa_version: Preprint
publication: arXiv
publication_status: submitted
status: public
title: Chromatic topological data analysis
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: preprint
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
year: '2024'
...
---
_id: '17891'
abstract:
- lang: eng
  text: "Abstract\r\nMethods used in topological data analysis naturally capture higher-order
    interactions in point cloud data embedded in a metric space. This methodology
    was recently extended to data living in an information space, by which we mean
    a space measured with an information theoretical distance. One such setting is
    a finite collection of discrete probability distributions embedded in the probability
    simplex measured with the relative entropy (Kullback–Leibler divergence). More
    generally, one can work with a Bregman divergence parameterized by a different
    notion of entropy. While theoretical algorithms exist for this setup, there is
    a paucity of implementations for exploring and comparing geometric-topological
    properties of various information spaces. The interest of this work is therefore
    twofold. First, we propose the first robust algorithms and software for geometric
    and topological data analysis in information space. Perhaps surprisingly, despite
    working with Bregman divergences, our design reuses robust libraries for the Euclidean
    case. Second, using the new software, we take the first steps towards understanding
    the geometric-topological structure of these spaces. In particular, we compare
    them with the more familiar spaces equipped with the Euclidean and Fisher metrics."
acknowledgement: We thank Anton Nikitenko for first observing that the Wrap complex
  can be characterized as stated in Claim (ii) of the Wrap Complex Lemma, and Ondrej
  Draganov for correcting a critical mistake in one of our formulas in Section 2.
article_number: '637'
article_processing_charge: Yes
article_type: original
author:
- first_name: Herbert
  full_name: Edelsbrunner, Herbert
  id: 3FB178DA-F248-11E8-B48F-1D18A9856A87
  last_name: Edelsbrunner
  orcid: 0000-0002-9823-6833
- first_name: Katharina
  full_name: Ölsböck, Katharina
  id: 4D4AA390-F248-11E8-B48F-1D18A9856A87
  last_name: Ölsböck
  orcid: 0000-0002-4672-8297
- first_name: Hubert
  full_name: Wagner, Hubert
  id: 379CA8B8-F248-11E8-B48F-1D18A9856A87
  last_name: Wagner
citation:
  ama: Edelsbrunner H, Ölsböck K, Wagner H. Understanding higher-order interactions
    in information space. <i>Entropy</i>. 2024;26(8). doi:<a href="https://doi.org/10.3390/e26080637">10.3390/e26080637</a>
  apa: Edelsbrunner, H., Ölsböck, K., &#38; Wagner, H. (2024). Understanding higher-order
    interactions in information space. <i>Entropy</i>. MDPI. <a href="https://doi.org/10.3390/e26080637">https://doi.org/10.3390/e26080637</a>
  chicago: Edelsbrunner, Herbert, Katharina Ölsböck, and Hubert Wagner. “Understanding
    Higher-Order Interactions in Information Space.” <i>Entropy</i>. MDPI, 2024. <a
    href="https://doi.org/10.3390/e26080637">https://doi.org/10.3390/e26080637</a>.
  ieee: H. Edelsbrunner, K. Ölsböck, and H. Wagner, “Understanding higher-order interactions
    in information space,” <i>Entropy</i>, vol. 26, no. 8. MDPI, 2024.
  ista: Edelsbrunner H, Ölsböck K, Wagner H. 2024. Understanding higher-order interactions
    in information space. Entropy. 26(8), 637.
  mla: Edelsbrunner, Herbert, et al. “Understanding Higher-Order Interactions in Information
    Space.” <i>Entropy</i>, vol. 26, no. 8, 637, MDPI, 2024, doi:<a href="https://doi.org/10.3390/e26080637">10.3390/e26080637</a>.
  short: H. Edelsbrunner, K. Ölsböck, H. Wagner, Entropy 26 (2024).
date_created: 2024-09-08T22:01:11Z
date_published: 2024-08-01T00:00:00Z
date_updated: 2025-09-08T09:13:44Z
day: '01'
ddc:
- '510'
department:
- _id: HeEd
doi: 10.3390/e26080637
external_id:
  isi:
  - '001305543500001'
  pmid:
  - '39202107'
file:
- access_level: open_access
  checksum: 624a9e2c5b49d6c38b88b0f675467ba3
  content_type: application/pdf
  creator: dernst
  date_created: 2024-09-09T09:01:12Z
  date_updated: 2024-09-09T09:01:12Z
  file_id: '17948'
  file_name: 2024_Entropy_Edelsbrunner.pdf
  file_size: 8025139
  relation: main_file
  success: 1
file_date_updated: 2024-09-09T09:01:12Z
has_accepted_license: '1'
intvolume: '        26'
isi: 1
issue: '8'
language:
- iso: eng
month: '08'
oa: 1
oa_version: Published Version
pmid: 1
publication: Entropy
publication_identifier:
  eissn:
  - 1099-4300
publication_status: published
publisher: MDPI
quality_controlled: '1'
related_material:
  link:
  - relation: software
    url: https://git.ista.ac.at/katharina.oelsboeck/wrap_2_3-public/
scopus_import: '1'
status: public
title: Understanding higher-order interactions in information space
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: 317138e5-6ab7-11ef-aa6d-ffef3953e345
volume: 26
year: '2024'
...
