---
_id: '7989'
abstract:
- lang: eng
  text: 'We prove general topological Radon-type theorems for sets in ℝ^d, smooth
    real manifolds or finite dimensional simplicial complexes. Combined with a recent
    result of Holmsen and Lee, it gives fractional Helly theorem, and consequently
    the existence of weak ε-nets as well as a (p,q)-theorem. More precisely: Let X
    be either ℝ^d, smooth real d-manifold, or a finite d-dimensional simplicial complex.
    Then if F is a finite, intersection-closed family of sets in X such that the ith
    reduced Betti number (with ℤ₂ coefficients) of any set in F is at most b for every
    non-negative integer i less or equal to k, then the Radon number of F is bounded
    in terms of b and X. Here k is the smallest integer larger or equal to d/2 - 1
    if X = ℝ^d; k=d-1 if X is a smooth real d-manifold and not a surface, k=0 if X
    is a surface and k=d if X is a d-dimensional simplicial complex. Using the recent
    result of the author and Kalai, we manage to prove the following optimal bound
    on fractional Helly number for families of open sets in a surface: Let F be a
    finite family of open sets in a surface S such that the intersection of any subfamily
    of F is either empty, or path-connected. Then the fractional Helly number of F
    is at most three. This also settles a conjecture of Holmsen, Kim, and Lee about
    an existence of a (p,q)-theorem for open subsets of a surface.'
alternative_title:
- LIPIcs
article_number: 61:1-61:13
article_processing_charge: No
arxiv: 1
author:
- first_name: Zuzana
  full_name: Patakova, Zuzana
  id: 48B57058-F248-11E8-B48F-1D18A9856A87
  last_name: Patakova
  orcid: 0000-0002-3975-1683
citation:
  ama: 'Patakova Z. Bounding radon number via Betti numbers. In: <i>36th International
    Symposium on Computational Geometry</i>. Vol 164. Schloss Dagstuhl - Leibniz-Zentrum
    für Informatik; 2020. doi:<a href="https://doi.org/10.4230/LIPIcs.SoCG.2020.61">10.4230/LIPIcs.SoCG.2020.61</a>'
  apa: 'Patakova, Z. (2020). Bounding radon number via Betti numbers. In <i>36th International
    Symposium on Computational Geometry</i> (Vol. 164). Zürich, Switzerland: Schloss
    Dagstuhl - Leibniz-Zentrum für Informatik. <a href="https://doi.org/10.4230/LIPIcs.SoCG.2020.61">https://doi.org/10.4230/LIPIcs.SoCG.2020.61</a>'
  chicago: Patakova, Zuzana. “Bounding Radon Number via Betti Numbers.” In <i>36th
    International Symposium on Computational Geometry</i>, Vol. 164. Schloss Dagstuhl
    - Leibniz-Zentrum für Informatik, 2020. <a href="https://doi.org/10.4230/LIPIcs.SoCG.2020.61">https://doi.org/10.4230/LIPIcs.SoCG.2020.61</a>.
  ieee: Z. Patakova, “Bounding radon number via Betti numbers,” in <i>36th International
    Symposium on Computational Geometry</i>, Zürich, Switzerland, 2020, vol. 164.
  ista: 'Patakova Z. 2020. Bounding radon number via Betti numbers. 36th International
    Symposium on Computational Geometry. SoCG: Symposium on Computational Geometry,
    LIPIcs, vol. 164, 61:1-61:13.'
  mla: Patakova, Zuzana. “Bounding Radon Number via Betti Numbers.” <i>36th International
    Symposium on Computational Geometry</i>, vol. 164, 61:1-61:13, Schloss Dagstuhl
    - Leibniz-Zentrum für Informatik, 2020, doi:<a href="https://doi.org/10.4230/LIPIcs.SoCG.2020.61">10.4230/LIPIcs.SoCG.2020.61</a>.
  short: Z. Patakova, in:, 36th International Symposium on Computational Geometry,
    Schloss Dagstuhl - Leibniz-Zentrum für Informatik, 2020.
conference:
  end_date: 2020-06-26
  location: Zürich, Switzerland
  name: 'SoCG: Symposium on Computational Geometry'
  start_date: 2020-06-22
date_created: 2020-06-22T09:14:18Z
date_published: 2020-06-01T00:00:00Z
date_updated: 2021-01-12T08:16:22Z
day: '01'
ddc:
- '510'
department:
- _id: UlWa
doi: 10.4230/LIPIcs.SoCG.2020.61
external_id:
  arxiv:
  - '1908.01677'
file:
- access_level: open_access
  checksum: d0996ca5f6eb32ce955ce782b4f2afbe
  content_type: application/pdf
  creator: dernst
  date_created: 2020-06-23T06:56:23Z
  date_updated: 2020-07-14T12:48:06Z
  file_id: '8005'
  file_name: 2020_LIPIcsSoCG_Patakova_61.pdf
  file_size: 645421
  relation: main_file
file_date_updated: 2020-07-14T12:48:06Z
has_accepted_license: '1'
intvolume: '       164'
language:
- iso: eng
month: '06'
oa: 1
oa_version: Published Version
publication: 36th International Symposium on Computational Geometry
publication_identifier:
  isbn:
  - '9783959771436'
  issn:
  - '18688969'
publication_status: published
publisher: Schloss Dagstuhl - Leibniz-Zentrum für Informatik
quality_controlled: '1'
scopus_import: '1'
status: public
title: Bounding radon number via Betti numbers
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: 164
year: '2020'
...
---
_id: '7990'
abstract:
- lang: eng
  text: 'Given a finite point set P in general position in the plane, a full triangulation
    is a maximal straight-line embedded plane graph on P. A partial triangulation
    on P is a full triangulation of some subset P'' of P containing all extreme points
    in P. A bistellar flip on a partial triangulation either flips an edge, removes
    a non-extreme point of degree 3, or adds a point in P ⧵ P'' as vertex of degree
    3. The bistellar flip graph has all partial triangulations as vertices, and a
    pair of partial triangulations is adjacent if they can be obtained from one another
    by a bistellar flip. The goal of this paper is to investigate the structure of
    this graph, with emphasis on its connectivity. For sets P of n points in general
    position, we show that the bistellar flip graph is (n-3)-connected, thereby answering,
    for sets in general position, an open questions raised in a book (by De Loera,
    Rambau, and Santos) and a survey (by Lee and Santos) on triangulations. This matches
    the situation for the subfamily of regular triangulations (i.e., partial triangulations
    obtained by lifting the points and projecting the lower convex hull), where (n-3)-connectivity
    has been known since the late 1980s through the secondary polytope (Gelfand, Kapranov,
    Zelevinsky) and Balinski’s Theorem. Our methods also yield the following results
    (see the full version [Wagner and Welzl, 2020]): (i) The bistellar flip graph
    can be covered by graphs of polytopes of dimension n-3 (products of secondary
    polytopes). (ii) A partial triangulation is regular, if it has distance n-3 in
    the Hasse diagram of the partial order of partial subdivisions from the trivial
    subdivision. (iii) All partial triangulations are regular iff the trivial subdivision
    has height n-3 in the partial order of partial subdivisions. (iv) There are arbitrarily
    large sets P with non-regular partial triangulations, while every proper subset
    has only regular triangulations, i.e., there are no small certificates for the
    existence of non-regular partial triangulations (answering a question by F. Santos
    in the unexpected direction).'
alternative_title:
- LIPIcs
article_number: 67:1 - 67:16
article_processing_charge: No
arxiv: 1
author:
- first_name: Uli
  full_name: Wagner, Uli
  id: 36690CA2-F248-11E8-B48F-1D18A9856A87
  last_name: Wagner
  orcid: 0000-0002-1494-0568
- first_name: Emo
  full_name: Welzl, Emo
  last_name: Welzl
citation:
  ama: 'Wagner U, Welzl E. Connectivity of triangulation flip graphs in the plane
    (Part II: Bistellar flips). In: <i>36th International Symposium on Computational
    Geometry</i>. Vol 164. Schloss Dagstuhl - Leibniz-Zentrum für Informatik; 2020.
    doi:<a href="https://doi.org/10.4230/LIPIcs.SoCG.2020.67">10.4230/LIPIcs.SoCG.2020.67</a>'
  apa: 'Wagner, U., &#38; Welzl, E. (2020). Connectivity of triangulation flip graphs
    in the plane (Part II: Bistellar flips). In <i>36th International Symposium on
    Computational Geometry</i> (Vol. 164). Zürich, Switzerland: Schloss Dagstuhl -
    Leibniz-Zentrum für Informatik. <a href="https://doi.org/10.4230/LIPIcs.SoCG.2020.67">https://doi.org/10.4230/LIPIcs.SoCG.2020.67</a>'
  chicago: 'Wagner, Uli, and Emo Welzl. “Connectivity of Triangulation Flip Graphs
    in the Plane (Part II: Bistellar Flips).” In <i>36th International Symposium on
    Computational Geometry</i>, Vol. 164. Schloss Dagstuhl - Leibniz-Zentrum für Informatik,
    2020. <a href="https://doi.org/10.4230/LIPIcs.SoCG.2020.67">https://doi.org/10.4230/LIPIcs.SoCG.2020.67</a>.'
  ieee: 'U. Wagner and E. Welzl, “Connectivity of triangulation flip graphs in the
    plane (Part II: Bistellar flips),” in <i>36th International Symposium on Computational
    Geometry</i>, Zürich, Switzerland, 2020, vol. 164.'
  ista: 'Wagner U, Welzl E. 2020. Connectivity of triangulation flip graphs in the
    plane (Part II: Bistellar flips). 36th International Symposium on Computational
    Geometry. SoCG: Symposium on Computational Geometry, LIPIcs, vol. 164, 67:1-67:16.'
  mla: 'Wagner, Uli, and Emo Welzl. “Connectivity of Triangulation Flip Graphs in
    the Plane (Part II: Bistellar Flips).” <i>36th International Symposium on Computational
    Geometry</i>, vol. 164, 67:1-67:16, Schloss Dagstuhl - Leibniz-Zentrum für Informatik,
    2020, doi:<a href="https://doi.org/10.4230/LIPIcs.SoCG.2020.67">10.4230/LIPIcs.SoCG.2020.67</a>.'
  short: U. Wagner, E. Welzl, in:, 36th International Symposium on Computational Geometry,
    Schloss Dagstuhl - Leibniz-Zentrum für Informatik, 2020.
conference:
  end_date: 2020-06-26
  location: Zürich, Switzerland
  name: 'SoCG: Symposium on Computational Geometry'
  start_date: 2020-06-22
date_created: 2020-06-22T09:14:19Z
date_published: 2020-06-01T00:00:00Z
date_updated: 2023-08-04T08:51:07Z
day: '01'
ddc:
- '510'
department:
- _id: UlWa
doi: 10.4230/LIPIcs.SoCG.2020.67
external_id:
  arxiv:
  - '2003.13557'
file:
- access_level: open_access
  checksum: 3f6925be5f3dcdb3b14cab92f410edf7
  content_type: application/pdf
  creator: dernst
  date_created: 2020-06-23T06:37:27Z
  date_updated: 2020-07-14T12:48:06Z
  file_id: '8003'
  file_name: 2020_LIPIcsSoCG_Wagner.pdf
  file_size: 793187
  relation: main_file
file_date_updated: 2020-07-14T12:48:06Z
has_accepted_license: '1'
intvolume: '       164'
language:
- iso: eng
month: '06'
oa: 1
oa_version: Published Version
publication: 36th International Symposium on Computational Geometry
publication_identifier:
  isbn:
  - '9783959771436'
  issn:
  - '18688969'
publication_status: published
publisher: Schloss Dagstuhl - Leibniz-Zentrum für Informatik
quality_controlled: '1'
related_material:
  record:
  - id: '12129'
    relation: later_version
    status: public
scopus_import: 1
status: public
title: 'Connectivity of triangulation flip graphs in the plane (Part II: Bistellar
  flips)'
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: 164
year: '2020'
...
---
_id: '7991'
abstract:
- lang: eng
  text: 'We define and study a discrete process that generalizes the convex-layer
    decomposition of a planar point set. Our process, which we call homotopic curve
    shortening (HCS), starts with a closed curve (which might self-intersect) in the
    presence of a set P⊂ ℝ² of point obstacles, and evolves in discrete steps, where
    each step consists of (1) taking shortcuts around the obstacles, and (2) reducing
    the curve to its shortest homotopic equivalent. We find experimentally that, if
    the initial curve is held fixed and P is chosen to be either a very fine regular
    grid or a uniformly random point set, then HCS behaves at the limit like the affine
    curve-shortening flow (ACSF). This connection between HCS and ACSF generalizes
    the link between "grid peeling" and the ACSF observed by Eppstein et al. (2017),
    which applied only to convex curves, and which was studied only for regular grids.
    We prove that HCS satisfies some properties analogous to those of ACSF: HCS is
    invariant under affine transformations, preserves convexity, and does not increase
    the total absolute curvature. Furthermore, the number of self-intersections of
    a curve, or intersections between two curves (appropriately defined), does not
    increase. Finally, if the initial curve is simple, then the number of inflection
    points (appropriately defined) does not increase.'
alternative_title:
- LIPIcs
article_number: 12:1 - 12:15
article_processing_charge: No
arxiv: 1
author:
- first_name: Sergey
  full_name: Avvakumov, Sergey
  id: 3827DAC8-F248-11E8-B48F-1D18A9856A87
  last_name: Avvakumov
- first_name: Gabriel
  full_name: Nivasch, Gabriel
  last_name: Nivasch
citation:
  ama: 'Avvakumov S, Nivasch G. Homotopic curve shortening and the affine curve-shortening
    flow. In: <i>36th International Symposium on Computational Geometry</i>. Vol 164.
    Schloss Dagstuhl - Leibniz-Zentrum für Informatik; 2020. doi:<a href="https://doi.org/10.4230/LIPIcs.SoCG.2020.12">10.4230/LIPIcs.SoCG.2020.12</a>'
  apa: 'Avvakumov, S., &#38; Nivasch, G. (2020). Homotopic curve shortening and the
    affine curve-shortening flow. In <i>36th International Symposium on Computational
    Geometry</i> (Vol. 164). Zürich, Switzerland: Schloss Dagstuhl - Leibniz-Zentrum
    für Informatik. <a href="https://doi.org/10.4230/LIPIcs.SoCG.2020.12">https://doi.org/10.4230/LIPIcs.SoCG.2020.12</a>'
  chicago: Avvakumov, Sergey, and Gabriel Nivasch. “Homotopic Curve Shortening and
    the Affine Curve-Shortening Flow.” In <i>36th International Symposium on Computational
    Geometry</i>, Vol. 164. Schloss Dagstuhl - Leibniz-Zentrum für Informatik, 2020.
    <a href="https://doi.org/10.4230/LIPIcs.SoCG.2020.12">https://doi.org/10.4230/LIPIcs.SoCG.2020.12</a>.
  ieee: S. Avvakumov and G. Nivasch, “Homotopic curve shortening and the affine curve-shortening
    flow,” in <i>36th International Symposium on Computational Geometry</i>, Zürich,
    Switzerland, 2020, vol. 164.
  ista: 'Avvakumov S, Nivasch G. 2020. Homotopic curve shortening and the affine curve-shortening
    flow. 36th International Symposium on Computational Geometry. SoCG: Symposium
    on Computational Geometry, LIPIcs, vol. 164, 12:1-12:15.'
  mla: Avvakumov, Sergey, and Gabriel Nivasch. “Homotopic Curve Shortening and the
    Affine Curve-Shortening Flow.” <i>36th International Symposium on Computational
    Geometry</i>, vol. 164, 12:1-12:15, Schloss Dagstuhl - Leibniz-Zentrum für Informatik,
    2020, doi:<a href="https://doi.org/10.4230/LIPIcs.SoCG.2020.12">10.4230/LIPIcs.SoCG.2020.12</a>.
  short: S. Avvakumov, G. Nivasch, in:, 36th International Symposium on Computational
    Geometry, Schloss Dagstuhl - Leibniz-Zentrum für Informatik, 2020.
conference:
  end_date: 2020-06-26
  location: Zürich, Switzerland
  name: 'SoCG: Symposium on Computational Geometry'
  start_date: 2020-06-22
date_created: 2020-06-22T09:14:19Z
date_published: 2020-06-01T00:00:00Z
date_updated: 2021-01-12T08:16:23Z
day: '01'
ddc:
- '510'
department:
- _id: UlWa
doi: 10.4230/LIPIcs.SoCG.2020.12
external_id:
  arxiv:
  - '1909.00263'
file:
- access_level: open_access
  checksum: 6872df6549142f709fb6354a1b2f2c06
  content_type: application/pdf
  creator: dernst
  date_created: 2020-06-23T11:13:49Z
  date_updated: 2020-07-14T12:48:06Z
  file_id: '8007'
  file_name: 2020_LIPIcsSoCG_Avvakumov.pdf
  file_size: 575896
  relation: main_file
file_date_updated: 2020-07-14T12:48:06Z
has_accepted_license: '1'
intvolume: '       164'
language:
- iso: eng
license: https://creativecommons.org/licenses/by/3.0/
month: '06'
oa: 1
oa_version: Published Version
project:
- _id: 26611F5C-B435-11E9-9278-68D0E5697425
  call_identifier: FWF
  grant_number: P31312
  name: Algorithms for Embeddings and Homotopy Theory
publication: 36th International Symposium on Computational Geometry
publication_identifier:
  isbn:
  - '9783959771436'
  issn:
  - '18688969'
publication_status: published
publisher: Schloss Dagstuhl - Leibniz-Zentrum für Informatik
quality_controlled: '1'
scopus_import: '1'
status: public
title: Homotopic curve shortening and the affine curve-shortening flow
tmp:
  image: /images/cc_by.png
  legal_code_url: https://creativecommons.org/licenses/by/3.0/legalcode
  name: Creative Commons Attribution 3.0 Unported (CC BY 3.0)
  short: CC BY (3.0)
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 164
year: '2020'
...
---
_id: '7992'
abstract:
- lang: eng
  text: 'Let K be a convex body in ℝⁿ (i.e., a compact convex set with nonempty interior).
    Given a point p in the interior of K, a hyperplane h passing through p is called
    barycentric if p is the barycenter of K ∩ h. In 1961, Grünbaum raised the question
    whether, for every K, there exists an interior point p through which there are
    at least n+1 distinct barycentric hyperplanes. Two years later, this was seemingly
    resolved affirmatively by showing that this is the case if p=p₀ is the point of
    maximal depth in K. However, while working on a related question, we noticed that
    one of the auxiliary claims in the proof is incorrect. Here, we provide a counterexample;
    this re-opens Grünbaum’s question. It follows from known results that for n ≥
    2, there are always at least three distinct barycentric cuts through the point
    p₀ ∈ K of maximal depth. Using tools related to Morse theory we are able to improve
    this bound: four distinct barycentric cuts through p₀ are guaranteed if n ≥ 3.'
alternative_title:
- LIPIcs
article_number: 62:1 - 62:16
article_processing_charge: No
arxiv: 1
author:
- first_name: Zuzana
  full_name: Patakova, Zuzana
  id: 48B57058-F248-11E8-B48F-1D18A9856A87
  last_name: Patakova
  orcid: 0000-0002-3975-1683
- first_name: Martin
  full_name: Tancer, Martin
  id: 38AC689C-F248-11E8-B48F-1D18A9856A87
  last_name: Tancer
  orcid: 0000-0002-1191-6714
- first_name: Uli
  full_name: Wagner, Uli
  id: 36690CA2-F248-11E8-B48F-1D18A9856A87
  last_name: Wagner
  orcid: 0000-0002-1494-0568
citation:
  ama: 'Patakova Z, Tancer M, Wagner U. Barycentric cuts through a convex body. In:
    <i>36th International Symposium on Computational Geometry</i>. Vol 164. Schloss
    Dagstuhl - Leibniz-Zentrum für Informatik; 2020. doi:<a href="https://doi.org/10.4230/LIPIcs.SoCG.2020.62">10.4230/LIPIcs.SoCG.2020.62</a>'
  apa: 'Patakova, Z., Tancer, M., &#38; Wagner, U. (2020). Barycentric cuts through
    a convex body. In <i>36th International Symposium on Computational Geometry</i>
    (Vol. 164). Zürich, Switzerland: Schloss Dagstuhl - Leibniz-Zentrum für Informatik.
    <a href="https://doi.org/10.4230/LIPIcs.SoCG.2020.62">https://doi.org/10.4230/LIPIcs.SoCG.2020.62</a>'
  chicago: Patakova, Zuzana, Martin Tancer, and Uli Wagner. “Barycentric Cuts through
    a Convex Body.” In <i>36th International Symposium on Computational Geometry</i>,
    Vol. 164. Schloss Dagstuhl - Leibniz-Zentrum für Informatik, 2020. <a href="https://doi.org/10.4230/LIPIcs.SoCG.2020.62">https://doi.org/10.4230/LIPIcs.SoCG.2020.62</a>.
  ieee: Z. Patakova, M. Tancer, and U. Wagner, “Barycentric cuts through a convex
    body,” in <i>36th International Symposium on Computational Geometry</i>, Zürich,
    Switzerland, 2020, vol. 164.
  ista: 'Patakova Z, Tancer M, Wagner U. 2020. Barycentric cuts through a convex body.
    36th International Symposium on Computational Geometry. SoCG: Symposium on Computational
    Geometry, LIPIcs, vol. 164, 62:1-62:16.'
  mla: Patakova, Zuzana, et al. “Barycentric Cuts through a Convex Body.” <i>36th
    International Symposium on Computational Geometry</i>, vol. 164, 62:1-62:16, Schloss
    Dagstuhl - Leibniz-Zentrum für Informatik, 2020, doi:<a href="https://doi.org/10.4230/LIPIcs.SoCG.2020.62">10.4230/LIPIcs.SoCG.2020.62</a>.
  short: Z. Patakova, M. Tancer, U. Wagner, in:, 36th International Symposium on Computational
    Geometry, Schloss Dagstuhl - Leibniz-Zentrum für Informatik, 2020.
conference:
  end_date: 2020-06-26
  location: Zürich, Switzerland
  name: 'SoCG: Symposium on Computational Geometry'
  start_date: 2020-06-22
date_created: 2020-06-22T09:14:20Z
date_published: 2020-06-01T00:00:00Z
date_updated: 2021-01-12T08:16:23Z
day: '01'
ddc:
- '510'
department:
- _id: UlWa
doi: 10.4230/LIPIcs.SoCG.2020.62
external_id:
  arxiv:
  - '2003.13536'
file:
- access_level: open_access
  checksum: ce1c9194139a664fb59d1efdfc88eaae
  content_type: application/pdf
  creator: dernst
  date_created: 2020-06-23T06:45:52Z
  date_updated: 2020-07-14T12:48:06Z
  file_id: '8004'
  file_name: 2020_LIPIcsSoCG_Patakova.pdf
  file_size: 750318
  relation: main_file
file_date_updated: 2020-07-14T12:48:06Z
has_accepted_license: '1'
intvolume: '       164'
language:
- iso: eng
month: '06'
oa: 1
oa_version: Published Version
publication: 36th International Symposium on Computational Geometry
publication_identifier:
  isbn:
  - '9783959771436'
  issn:
  - '18688969'
publication_status: published
publisher: Schloss Dagstuhl - Leibniz-Zentrum für Informatik
quality_controlled: '1'
scopus_import: 1
status: public
title: Barycentric cuts through a convex body
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: 164
year: '2020'
...
---
_id: '7994'
abstract:
- lang: eng
  text: In the recent study of crossing numbers, drawings of graphs that can be extended
    to an arrangement of pseudolines (pseudolinear drawings) have played an important
    role as they are a natural combinatorial extension of rectilinear (or straight-line)
    drawings. A characterization of the pseudolinear drawings of K_n was found recently.
    We extend this characterization to all graphs, by describing the set of minimal
    forbidden subdrawings for pseudolinear drawings. Our characterization also leads
    to a polynomial-time algorithm to recognize pseudolinear drawings and construct
    the pseudolines when it is possible.
alternative_title:
- LIPIcs
article_number: 9:1 - 9:14
article_processing_charge: No
arxiv: 1
author:
- first_name: Alan M
  full_name: Arroyo Guevara, Alan M
  id: 3207FDC6-F248-11E8-B48F-1D18A9856A87
  last_name: Arroyo Guevara
  orcid: 0000-0003-2401-8670
- first_name: Julien
  full_name: Bensmail, Julien
  last_name: Bensmail
- first_name: R.
  full_name: Bruce Richter, R.
  last_name: Bruce Richter
citation:
  ama: 'Arroyo Guevara AM, Bensmail J, Bruce Richter R. Extending drawings of graphs
    to arrangements of pseudolines. In: <i>36th International Symposium on Computational
    Geometry</i>. Vol 164. Schloss Dagstuhl - Leibniz-Zentrum für Informatik; 2020.
    doi:<a href="https://doi.org/10.4230/LIPIcs.SoCG.2020.9">10.4230/LIPIcs.SoCG.2020.9</a>'
  apa: 'Arroyo Guevara, A. M., Bensmail, J., &#38; Bruce Richter, R. (2020). Extending
    drawings of graphs to arrangements of pseudolines. In <i>36th International Symposium
    on Computational Geometry</i> (Vol. 164). Zürich, Switzerland: Schloss Dagstuhl
    - Leibniz-Zentrum für Informatik. <a href="https://doi.org/10.4230/LIPIcs.SoCG.2020.9">https://doi.org/10.4230/LIPIcs.SoCG.2020.9</a>'
  chicago: Arroyo Guevara, Alan M, Julien Bensmail, and R. Bruce Richter. “Extending
    Drawings of Graphs to Arrangements of Pseudolines.” In <i>36th International Symposium
    on Computational Geometry</i>, Vol. 164. Schloss Dagstuhl - Leibniz-Zentrum für
    Informatik, 2020. <a href="https://doi.org/10.4230/LIPIcs.SoCG.2020.9">https://doi.org/10.4230/LIPIcs.SoCG.2020.9</a>.
  ieee: A. M. Arroyo Guevara, J. Bensmail, and R. Bruce Richter, “Extending drawings
    of graphs to arrangements of pseudolines,” in <i>36th International Symposium
    on Computational Geometry</i>, Zürich, Switzerland, 2020, vol. 164.
  ista: 'Arroyo Guevara AM, Bensmail J, Bruce Richter R. 2020. Extending drawings
    of graphs to arrangements of pseudolines. 36th International Symposium on Computational
    Geometry. SoCG: Symposium on Computational Geometry, LIPIcs, vol. 164, 9:1-9:14.'
  mla: Arroyo Guevara, Alan M., et al. “Extending Drawings of Graphs to Arrangements
    of Pseudolines.” <i>36th International Symposium on Computational Geometry</i>,
    vol. 164, 9:1-9:14, Schloss Dagstuhl - Leibniz-Zentrum für Informatik, 2020, doi:<a
    href="https://doi.org/10.4230/LIPIcs.SoCG.2020.9">10.4230/LIPIcs.SoCG.2020.9</a>.
  short: A.M. Arroyo Guevara, J. Bensmail, R. Bruce Richter, in:, 36th International
    Symposium on Computational Geometry, Schloss Dagstuhl - Leibniz-Zentrum für Informatik,
    2020.
conference:
  end_date: 2020-06-26
  location: Zürich, Switzerland
  name: 'SoCG: Symposium on Computational Geometry'
  start_date: 2020-06-22
date_created: 2020-06-22T09:14:21Z
date_published: 2020-06-01T00:00:00Z
date_updated: 2023-02-23T13:22:12Z
day: '01'
ddc:
- '510'
department:
- _id: UlWa
doi: 10.4230/LIPIcs.SoCG.2020.9
ec_funded: 1
external_id:
  arxiv:
  - '1804.09317'
file:
- access_level: open_access
  checksum: 93571b76cf97d5b7c8aabaeaa694dd7e
  content_type: application/pdf
  creator: dernst
  date_created: 2020-06-23T11:06:23Z
  date_updated: 2020-07-14T12:48:06Z
  file_id: '8006'
  file_name: 2020_LIPIcsSoCG_Arroyo.pdf
  file_size: 592661
  relation: main_file
file_date_updated: 2020-07-14T12:48:06Z
has_accepted_license: '1'
intvolume: '       164'
language:
- iso: eng
month: '06'
oa: 1
oa_version: Published Version
project:
- _id: 260C2330-B435-11E9-9278-68D0E5697425
  call_identifier: H2020
  grant_number: '754411'
  name: ISTplus - Postdoctoral Fellowships
publication: 36th International Symposium on Computational Geometry
publication_identifier:
  isbn:
  - '9783959771436'
  issn:
  - '18688969'
publication_status: published
publisher: Schloss Dagstuhl - Leibniz-Zentrum für Informatik
quality_controlled: '1'
scopus_import: '1'
status: public
title: Extending drawings of graphs to arrangements of pseudolines
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: 164
year: '2020'
...
---
_id: '11824'
abstract:
- lang: eng
  text: "Independent set is a fundamental problem in combinatorial optimization. While
    in general graphs the problem is essentially inapproximable, for many important
    graph classes there are approximation algorithms known in the offline setting.
    These graph classes include interval graphs and geometric intersection graphs,
    where vertices correspond to intervals/geometric objects and an edge indicates
    that the two corresponding objects intersect.\r\nWe present dynamic approximation
    algorithms for independent set of intervals, hypercubes and hyperrectangles in
    d dimensions. They work in the fully dynamic model where each update inserts or
    deletes a geometric object. All our algorithms are deterministic and have worst-case
    update times that are polylogarithmic for constant d and ε>0, assuming that the
    coordinates of all input objects are in [0, N]^d and each of their edges has length
    at least 1. We obtain the following results:\r\n- For weighted intervals, we maintain
    a (1+ε)-approximate solution.\r\n- For d-dimensional hypercubes we maintain a
    (1+ε)2^d-approximate solution in the unweighted case and a O(2^d)-approximate
    solution in the weighted case. Also, we show that for maintaining an unweighted
    (1+ε)-approximate solution one needs polynomial update time for d ≥ 2 if the ETH
    holds.\r\n- For weighted d-dimensional hyperrectangles we present a dynamic algorithm
    with approximation ratio (1+ε)log^{d-1}N."
alternative_title:
- LIPIcs
article_number: '51'
article_processing_charge: No
arxiv: 1
author:
- 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: Stefan
  full_name: Neumann, Stefan
  last_name: Neumann
- first_name: Andreas
  full_name: Wiese, Andreas
  last_name: Wiese
citation:
  ama: 'Henzinger MH, Neumann S, Wiese A. Dynamic approximate maximum independent
    set of intervals, hypercubes and hyperrectangles. In: <i>36th International Symposium
    on Computational Geometry</i>. Vol 164. Schloss Dagstuhl - Leibniz-Zentrum für
    Informatik; 2020. doi:<a href="https://doi.org/10.4230/LIPIcs.SoCG.2020.51">10.4230/LIPIcs.SoCG.2020.51</a>'
  apa: 'Henzinger, M. H., Neumann, S., &#38; Wiese, A. (2020). Dynamic approximate
    maximum independent set of intervals, hypercubes and hyperrectangles. In <i>36th
    International Symposium on Computational Geometry</i> (Vol. 164). Zurich, Switzerland:
    Schloss Dagstuhl - Leibniz-Zentrum für Informatik. <a href="https://doi.org/10.4230/LIPIcs.SoCG.2020.51">https://doi.org/10.4230/LIPIcs.SoCG.2020.51</a>'
  chicago: Henzinger, Monika H, Stefan Neumann, and Andreas Wiese. “Dynamic Approximate
    Maximum Independent Set of Intervals, Hypercubes and Hyperrectangles.” In <i>36th
    International Symposium on Computational Geometry</i>, Vol. 164. Schloss Dagstuhl
    - Leibniz-Zentrum für Informatik, 2020. <a href="https://doi.org/10.4230/LIPIcs.SoCG.2020.51">https://doi.org/10.4230/LIPIcs.SoCG.2020.51</a>.
  ieee: M. H. Henzinger, S. Neumann, and A. Wiese, “Dynamic approximate maximum independent
    set of intervals, hypercubes and hyperrectangles,” in <i>36th International Symposium
    on Computational Geometry</i>, Zurich, Switzerland, 2020, vol. 164.
  ista: 'Henzinger MH, Neumann S, Wiese A. 2020. Dynamic approximate maximum independent
    set of intervals, hypercubes and hyperrectangles. 36th International Symposium
    on Computational Geometry. SoCG: Symposium on Computational Geometry, LIPIcs,
    vol. 164, 51.'
  mla: Henzinger, Monika H., et al. “Dynamic Approximate Maximum Independent Set of
    Intervals, Hypercubes and Hyperrectangles.” <i>36th International Symposium on
    Computational Geometry</i>, vol. 164, 51, Schloss Dagstuhl - Leibniz-Zentrum für
    Informatik, 2020, doi:<a href="https://doi.org/10.4230/LIPIcs.SoCG.2020.51">10.4230/LIPIcs.SoCG.2020.51</a>.
  short: M.H. Henzinger, S. Neumann, A. Wiese, in:, 36th International Symposium on
    Computational Geometry, Schloss Dagstuhl - Leibniz-Zentrum für Informatik, 2020.
conference:
  end_date: 2020-06-26
  location: Zurich, Switzerland
  name: 'SoCG: Symposium on Computational Geometry'
  start_date: 2020-06-23
date_created: 2022-08-12T07:46:44Z
date_published: 2020-06-08T00:00:00Z
date_updated: 2023-02-14T10:00:58Z
day: '08'
doi: 10.4230/LIPIcs.SoCG.2020.51
extern: '1'
external_id:
  arxiv:
  - '2003.02605'
intvolume: '       164'
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://doi.org/10.4230/LIPIcs.SoCG.2020.51
month: '06'
oa: 1
oa_version: Published Version
publication: 36th International Symposium on Computational Geometry
publication_identifier:
  isbn:
  - '9783959771436'
  issn:
  - 1868-8969
publication_status: published
publisher: Schloss Dagstuhl - Leibniz-Zentrum für Informatik
quality_controlled: '1'
scopus_import: '1'
status: public
title: Dynamic approximate maximum independent set of intervals, hypercubes and hyperrectangles
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 164
year: '2020'
...
