---
_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:
- access_level: open_access
  checksum: b40ff456c19294adb5d9613fcfd751c6
  content_type: application/pdf
  creator: dernst
  date_created: 2024-06-17T08:33:40Z
  date_updated: 2024-06-17T08:33:40Z
  file_id: '17150'
  file_name: 2024_LIPICS_Kourimska.pdf
  file_size: 1612558
  relation: main_file
  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: '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: '18097'
abstract:
- lang: eng
  text: "In our companion paper \"Tight bounds for the learning of homotopy à la Niyogi,
    Smale, and Weinberger for subsets of Euclidean spaces and of Riemannian manifolds\"
    we gave optimal bounds (in terms of the two one-sided Hausdorff distances) on
    a sample P of an input shape \U0001D4AE (either manifold or general set with positive
    reach) such that one can infer the homotopy of \U0001D4AE from the union of balls
    with some radius centred at P, both in Euclidean space and in a Riemannian manifold
    of bounded curvature. The construction showing the optimality of the bounds is
    not straightforward. The purpose of this video is to visualize and thus elucidate
    said construction in the Euclidean setting."
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. I02979-N35. Mathijs Wintraecken: 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.\r\nWe
  thank Jean-Daniel Boissonnat, Herbert Edelsbrunner, and Mariette Yvinec for discussion."
alternative_title:
- LIPIcs
article_number: '87'
article_processing_charge: Yes
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: Andre
  full_name: Lieutier, Andre
  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. The ultimate frontier: An optimality
    construction for homotopy inference (media exposition). 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.2024.87">10.4230/LIPIcs.SoCG.2024.87</a>'
  apa: 'Attali, D., Kourimska, H., Fillmore, C. D., Ghosh, I., Lieutier, A., Stephenson,
    E. R., &#38; Wintraecken, M. (2024). The ultimate frontier: An optimality construction
    for homotopy inference (media exposition). 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.2024.87">https://doi.org/10.4230/LIPIcs.SoCG.2024.87</a>'
  chicago: 'Attali, Dominique, Hana Kourimska, Christopher D Fillmore, Ishika Ghosh,
    Andre Lieutier, Elizabeth R Stephenson, and Mathijs Wintraecken. “The Ultimate
    Frontier: An Optimality Construction for Homotopy Inference (Media Exposition).”
    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.2024.87">https://doi.org/10.4230/LIPIcs.SoCG.2024.87</a>.'
  ieee: 'D. Attali <i>et al.</i>, “The ultimate frontier: An optimality construction
    for homotopy inference (media exposition),” in <i>40th International Symposium
    on Computational Geometry</i>, Athens, Greece, 2024, vol. 293.'
  ista: 'Attali D, Kourimska H, Fillmore CD, Ghosh I, Lieutier A, Stephenson ER, Wintraecken
    M. 2024. The ultimate frontier: An optimality construction for homotopy inference
    (media exposition). 40th International Symposium on Computational Geometry. SoCG:
    Symposium on Computational Geometry, LIPIcs, vol. 293, 87.'
  mla: 'Attali, Dominique, et al. “The Ultimate Frontier: An Optimality Construction
    for Homotopy Inference (Media Exposition).” <i>40th International Symposium on
    Computational Geometry</i>, vol. 293, 87, Schloss Dagstuhl - Leibniz-Zentrum für
    Informatik, 2024, doi:<a href="https://doi.org/10.4230/LIPIcs.SoCG.2024.87">10.4230/LIPIcs.SoCG.2024.87</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.
conference:
  end_date: 2024-06-14
  location: Athens, Greece
  name: 'SoCG: Symposium on Computational Geometry'
  start_date: 2024-06-11
corr_author: '1'
date_created: 2024-09-19T10:29:48Z
date_published: 2024-06-06T00:00:00Z
date_updated: 2025-04-15T07:16:58Z
day: '06'
ddc:
- '000'
department:
- _id: HeEd
doi: 10.4230/LIPIcs.SoCG.2024.87
ec_funded: 1
file:
- access_level: open_access
  checksum: 9355c2e60b8ec285e1b22719c5b73f1a
  content_type: application/pdf
  creator: dernst
  date_created: 2024-09-19T10:30:37Z
  date_updated: 2024-09-19T10:30:37Z
  file_id: '18098'
  file_name: 2024_LIPICs_Attali.pdf
  file_size: 3507177
  relation: main_file
  success: 1
file_date_updated: 2024-09-19T10:30:37Z
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'
publication_status: published
publisher: Schloss Dagstuhl - Leibniz-Zentrum für Informatik
quality_controlled: '1'
status: public
title: 'The ultimate frontier: An optimality construction for homotopy inference (media
  exposition)'
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'
...
---
OA_place: publisher
OA_type: gold
_id: '18917'
abstract:
- lang: eng
  text: "An eight-partition of a finite set of points (respectively, of a continuous
    mass distribution) in ℝ³ consists of three planes that divide the space into 8
    octants, such that each open octant contains at most 1/8 of the points (respectively,
    of the mass). In 1966, Hadwiger showed that any mass distribution in ℝ³ admits
    an eight-partition; moreover, one can prescribe the normal direction of one of
    the three planes. The analogous result for finite point sets follows by a standard
    limit argument.\r\nWe prove the following variant of this result: Any mass distribution
    (or point set) in ℝ³ admits an eight-partition for which the intersection of two
    of the planes is a line with a prescribed direction.\r\nMoreover, we present an
    efficient algorithm for calculating an eight-partition of a set of n points in
    ℝ³ (with prescribed normal direction of one of the planes) in time O^*(n^{5/2})."
acknowledgement: "Aronov, Boris: Work has been supported by NSF grants CCF 15-40656
  and CCF 20-08551, and by grant 2014/170 from the US-Israel Binational Science Foundation.
  Part of this research was conducted while BA was visiting ISTA in the summers of
  2022 and 2023. The visit of BA to ISTA in the summer of 2022 was supported by an
  ISTA Visiting Professorship.\r\nBasit, Abdul: Work has been supported by Australian
  Research Council grant DP220102212.\r\nRamesh, Indu: Work supported by a Tandon
  School of Engineering Fellowship and by NSF Grant CCF-20-08551.\r\nBA and AB would
  like to thank William Steiger for insightful initial discussions of the problems
  addressed in this work."
article_processing_charge: Yes
arxiv: 1
author:
- first_name: Boris
  full_name: Aronov, Boris
  last_name: Aronov
- first_name: Abdul
  full_name: Basit, Abdul
  last_name: Basit
- first_name: Indu
  full_name: Ramesh, Indu
  last_name: Ramesh
- first_name: Gianluca
  full_name: Tasinato, Gianluca
  id: 0433290C-AF8F-11E9-A4C7-F729E6697425
  last_name: Tasinato
- first_name: Uli
  full_name: Wagner, Uli
  id: 36690CA2-F248-11E8-B48F-1D18A9856A87
  last_name: Wagner
  orcid: 0000-0002-1494-0568
citation:
  ama: 'Aronov B, Basit A, Ramesh I, Tasinato G, Wagner U. Eight-partitioning points
    in 3D, and efficiently too. In: <i>40th International Symposium on Computational
    Geometry</i>. Vol 293. Schloss Dagstuhl - Leibniz-Zentrum für Informatik; 2024:8:1-8:15.
    doi:<a href="https://doi.org/10.4230/LIPIcs.SoCG.2024.8">10.4230/LIPIcs.SoCG.2024.8</a>'
  apa: 'Aronov, B., Basit, A., Ramesh, I., Tasinato, G., &#38; Wagner, U. (2024).
    Eight-partitioning points in 3D, and efficiently too. In <i>40th International
    Symposium on Computational Geometry</i> (Vol. 293, p. 8:1-8:15). Athens, Greece:
    Schloss Dagstuhl - Leibniz-Zentrum für Informatik. <a href="https://doi.org/10.4230/LIPIcs.SoCG.2024.8">https://doi.org/10.4230/LIPIcs.SoCG.2024.8</a>'
  chicago: Aronov, Boris, Abdul Basit, Indu Ramesh, Gianluca Tasinato, and Uli Wagner.
    “Eight-Partitioning Points in 3D, and Efficiently Too.” In <i>40th International
    Symposium on Computational Geometry</i>, 293:8:1-8:15. Schloss Dagstuhl - Leibniz-Zentrum
    für Informatik, 2024. <a href="https://doi.org/10.4230/LIPIcs.SoCG.2024.8">https://doi.org/10.4230/LIPIcs.SoCG.2024.8</a>.
  ieee: B. Aronov, A. Basit, I. Ramesh, G. Tasinato, and U. Wagner, “Eight-partitioning
    points in 3D, and efficiently too,” in <i>40th International Symposium on Computational
    Geometry</i>, Athens, Greece, 2024, vol. 293, p. 8:1-8:15.
  ista: 'Aronov B, Basit A, Ramesh I, Tasinato G, Wagner U. 2024. Eight-partitioning
    points in 3D, and efficiently too. 40th International Symposium on Computational
    Geometry. SoCG: Symposium on Computational Geometry vol. 293, 8:1-8:15.'
  mla: Aronov, Boris, et al. “Eight-Partitioning Points in 3D, and Efficiently Too.”
    <i>40th International Symposium on Computational Geometry</i>, vol. 293, Schloss
    Dagstuhl - Leibniz-Zentrum für Informatik, 2024, p. 8:1-8:15, doi:<a href="https://doi.org/10.4230/LIPIcs.SoCG.2024.8">10.4230/LIPIcs.SoCG.2024.8</a>.
  short: B. Aronov, A. Basit, I. Ramesh, G. Tasinato, U. Wagner, in:, 40th International
    Symposium on Computational Geometry, Schloss Dagstuhl - Leibniz-Zentrum für Informatik,
    2024, p. 8:1-8:15.
conference:
  end_date: 2024-06-14
  location: Athens, Greece
  name: 'SoCG: Symposium on Computational Geometry'
  start_date: 2024-06-11
corr_author: '1'
date_created: 2025-01-27T14:19:17Z
date_published: 2024-06-06T00:00:00Z
date_updated: 2026-07-23T11:14:45Z
day: '06'
ddc:
- '510'
department:
- _id: UlWa
- _id: GradSch
doi: 10.4230/LIPIcs.SoCG.2024.8
external_id:
  arxiv:
  - '2403.02627'
file:
- access_level: open_access
  checksum: 443aa29ea5d948e917cfccd681dcf176
  content_type: application/pdf
  creator: dernst
  date_created: 2025-01-27T14:17:37Z
  date_updated: 2025-01-27T14:17:37Z
  file_id: '18918'
  file_name: 2024_LIPICs_Aronov.pdf
  file_size: 880725
  relation: main_file
  success: 1
file_date_updated: 2025-01-27T14:17:37Z
has_accepted_license: '1'
intvolume: '       293'
language:
- iso: eng
month: '06'
oa: 1
oa_version: Published Version
page: 8:1-8:15
publication: 40th International Symposium on Computational Geometry
publication_identifier:
  isbn:
  - '9783959773164'
publication_status: published
publisher: Schloss Dagstuhl - Leibniz-Zentrum für Informatik
quality_controlled: '1'
related_material:
  record:
  - id: '19860'
    relation: later_version
    status: public
scopus_import: '1'
status: public
title: Eight-partitioning points in 3D, and efficiently too
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: 2026-07-27T08:15:58Z
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'
...
