---
_id: '433'
abstract:
- lang: eng
text: 'A thrackle is a graph drawn in the plane so that every pair of its edges
meet exactly once: either at a common end vertex or in a proper crossing. We prove
that any thrackle of n vertices has at most 1.3984n edges. Quasi-thrackles are
defined similarly, except that every pair of edges that do not share a vertex
are allowed to cross an odd number of times. It is also shown that the maximum
number of edges of a quasi-thrackle on n vertices is 3/2(n-1), and that this bound
is best possible for infinitely many values of n.'
alternative_title:
- LNCS
author:
- first_name: Radoslav
full_name: Fulek, Radoslav
id: 39F3FFE4-F248-11E8-B48F-1D18A9856A87
last_name: Fulek
orcid: 0000-0001-8485-1774
- first_name: János
full_name: Pach, János
last_name: Pach
citation:
ama: 'Fulek R, Pach J. Thrackles: An improved upper bound. In: Vol 10692. Springer;
2018:160-166. doi:10.1007/978-3-319-73915-1_14'
apa: 'Fulek, R., & Pach, J. (2018). Thrackles: An improved upper bound (Vol.
10692, pp. 160–166). Presented at the GD 2017: Graph Drawing and Network Visualization,
Boston, MA, United States: Springer. https://doi.org/10.1007/978-3-319-73915-1_14'
chicago: 'Fulek, Radoslav, and János Pach. “Thrackles: An Improved Upper Bound,”
10692:160–66. Springer, 2018. https://doi.org/10.1007/978-3-319-73915-1_14.'
ieee: 'R. Fulek and J. Pach, “Thrackles: An improved upper bound,” presented at
the GD 2017: Graph Drawing and Network Visualization, Boston, MA, United States,
2018, vol. 10692, pp. 160–166.'
ista: 'Fulek R, Pach J. 2018. Thrackles: An improved upper bound. GD 2017: Graph
Drawing and Network Visualization, LNCS, vol. 10692, 160–166.'
mla: 'Fulek, Radoslav, and János Pach. Thrackles: An Improved Upper Bound.
Vol. 10692, Springer, 2018, pp. 160–66, doi:10.1007/978-3-319-73915-1_14.'
short: R. Fulek, J. Pach, in:, Springer, 2018, pp. 160–166.
conference:
end_date: 2017-09-27
location: Boston, MA, United States
name: 'GD 2017: Graph Drawing and Network Visualization'
start_date: 201-09-25
date_created: 2018-12-11T11:46:27Z
date_published: 2018-01-21T00:00:00Z
date_updated: 2023-08-24T14:39:32Z
day: '21'
department:
- _id: UlWa
doi: 10.1007/978-3-319-73915-1_14
external_id:
arxiv:
- '1708.08037'
intvolume: ' 10692'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://arxiv.org/abs/1708.08037
month: '01'
oa: 1
oa_version: Submitted Version
page: 160 - 166
publication_status: published
publisher: Springer
publist_id: '7390'
quality_controlled: '1'
related_material:
record:
- id: '5857'
relation: later_version
status: public
scopus_import: 1
status: public
title: 'Thrackles: An improved upper bound'
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 10692
year: '2018'
...
---
_id: '9837'
abstract:
- lang: eng
text: Both classical and recent studies suggest that chromosomal inversion polymorphisms
are important in adaptation and speciation. However, biases in discovery and reporting
of inversions make it difficult to assess their prevalence and biological importance.
Here, we use an approach based on linkage disequilibrium among markers genotyped
for samples collected across a transect between contrasting habitats to detect
chromosomal rearrangements de novo. We report 17 polymorphic rearrangements in
a single locality for the coastal marine snail, Littorina saxatilis. Patterns
of diversity in the field and of recombination in controlled crosses provide strong
evidence that at least the majority of these rearrangements are inversions. Most
show clinal changes in frequency between habitats, suggestive of divergent selection,
but only one appears to be fixed for different arrangements in the two habitats.
Consistent with widespread evidence for balancing selection on inversion polymorphisms,
we argue that a combination of heterosis and divergent selection can explain the
observed patterns and should be considered in other systems spanning environmental
gradients.
article_processing_charge: No
author:
- first_name: Rui
full_name: Faria, Rui
last_name: Faria
- first_name: Pragya
full_name: Chaube, Pragya
last_name: Chaube
- first_name: Hernán E.
full_name: Morales, Hernán E.
last_name: Morales
- first_name: Tomas
full_name: Larsson, Tomas
last_name: Larsson
- first_name: Alan R.
full_name: Lemmon, Alan R.
last_name: Lemmon
- first_name: Emily M.
full_name: Lemmon, Emily M.
last_name: Lemmon
- first_name: Marina
full_name: Rafajlović, Marina
last_name: Rafajlović
- first_name: Marina
full_name: Panova, Marina
last_name: Panova
- first_name: Mark
full_name: Ravinet, Mark
last_name: Ravinet
- first_name: Kerstin
full_name: Johannesson, Kerstin
last_name: Johannesson
- first_name: Anja M
full_name: Westram, Anja M
id: 3C147470-F248-11E8-B48F-1D18A9856A87
last_name: Westram
orcid: 0000-0003-1050-4969
- first_name: Roger K.
full_name: Butlin, Roger K.
last_name: Butlin
citation:
ama: 'Faria R, Chaube P, Morales HE, et al. Data from: Multiple chromosomal rearrangements
in a hybrid zone between Littorina saxatilis ecotypes. 2018. doi:10.5061/dryad.72cg113'
apa: 'Faria, R., Chaube, P., Morales, H. E., Larsson, T., Lemmon, A. R., Lemmon,
E. M., … Butlin, R. K. (2018). Data from: Multiple chromosomal rearrangements
in a hybrid zone between Littorina saxatilis ecotypes. Dryad. https://doi.org/10.5061/dryad.72cg113'
chicago: 'Faria, Rui, Pragya Chaube, Hernán E. Morales, Tomas Larsson, Alan R. Lemmon,
Emily M. Lemmon, Marina Rafajlović, et al. “Data from: Multiple Chromosomal Rearrangements
in a Hybrid Zone between Littorina Saxatilis Ecotypes.” Dryad, 2018. https://doi.org/10.5061/dryad.72cg113.'
ieee: 'R. Faria et al., “Data from: Multiple chromosomal rearrangements in
a hybrid zone between Littorina saxatilis ecotypes.” Dryad, 2018.'
ista: 'Faria R, Chaube P, Morales HE, Larsson T, Lemmon AR, Lemmon EM, Rafajlović
M, Panova M, Ravinet M, Johannesson K, Westram AM, Butlin RK. 2018. Data from:
Multiple chromosomal rearrangements in a hybrid zone between Littorina saxatilis
ecotypes, Dryad, 10.5061/dryad.72cg113.'
mla: 'Faria, Rui, et al. Data from: Multiple Chromosomal Rearrangements in a
Hybrid Zone between Littorina Saxatilis Ecotypes. Dryad, 2018, doi:10.5061/dryad.72cg113.'
short: R. Faria, P. Chaube, H.E. Morales, T. Larsson, A.R. Lemmon, E.M. Lemmon,
M. Rafajlović, M. Panova, M. Ravinet, K. Johannesson, A.M. Westram, R.K. Butlin,
(2018).
date_created: 2021-08-09T12:46:39Z
date_published: 2018-10-09T00:00:00Z
date_updated: 2023-08-24T14:50:26Z
day: '09'
department:
- _id: NiBa
doi: 10.5061/dryad.72cg113
main_file_link:
- open_access: '1'
url: https://doi.org/10.5061/dryad.72cg113
month: '10'
oa: 1
oa_version: Published Version
publisher: Dryad
related_material:
record:
- id: '6095'
relation: used_in_publication
status: public
status: public
title: 'Data from: Multiple chromosomal rearrangements in a hybrid zone between Littorina
saxatilis ecotypes'
type: research_data_reference
user_id: 6785fbc1-c503-11eb-8a32-93094b40e1cf
year: '2018'
...
---
_id: '10864'
abstract:
- lang: eng
text: We prove that every congruence distributive variety has directed Jónsson terms,
and every congruence modular variety has directed Gumm terms. The directed terms
we construct witness every case of absorption witnessed by the original Jónsson
or Gumm terms. This result is equivalent to a pair of claims about absorption
for admissible preorders in congruence distributive and congruence modular varieties,
respectively. For finite algebras, these absorption theorems have already seen
significant applications, but until now, it was not clear if the theorems hold
for general algebras as well. Our method also yields a novel proof of a result
by P. Lipparini about the existence of a chain of terms (which we call Pixley
terms) in varieties that are at the same time congruence distributive and k-permutable
for some k.
acknowledgement: The second author was supported by National Science Center grant
DEC-2011-/01/B/ST6/01006.
article_processing_charge: No
author:
- first_name: Alexandr
full_name: Kazda, Alexandr
id: 3B32BAA8-F248-11E8-B48F-1D18A9856A87
last_name: Kazda
- first_name: Marcin
full_name: Kozik, Marcin
last_name: Kozik
- first_name: Ralph
full_name: McKenzie, Ralph
last_name: McKenzie
- first_name: Matthew
full_name: Moore, Matthew
last_name: Moore
citation:
ama: 'Kazda A, Kozik M, McKenzie R, Moore M. Absorption and directed Jónsson terms.
In: Czelakowski J, ed. Don Pigozzi on Abstract Algebraic Logic, Universal Algebra,
and Computer Science. Vol 16. OCTR. Cham: Springer Nature; 2018:203-220. doi:10.1007/978-3-319-74772-9_7'
apa: 'Kazda, A., Kozik, M., McKenzie, R., & Moore, M. (2018). Absorption and
directed Jónsson terms. In J. Czelakowski (Ed.), Don Pigozzi on Abstract Algebraic
Logic, Universal Algebra, and Computer Science (Vol. 16, pp. 203–220). Cham:
Springer Nature. https://doi.org/10.1007/978-3-319-74772-9_7'
chicago: 'Kazda, Alexandr, Marcin Kozik, Ralph McKenzie, and Matthew Moore. “Absorption
and Directed Jónsson Terms.” In Don Pigozzi on Abstract Algebraic Logic, Universal
Algebra, and Computer Science, edited by J Czelakowski, 16:203–20. OCTR. Cham:
Springer Nature, 2018. https://doi.org/10.1007/978-3-319-74772-9_7.'
ieee: 'A. Kazda, M. Kozik, R. McKenzie, and M. Moore, “Absorption and directed Jónsson
terms,” in Don Pigozzi on Abstract Algebraic Logic, Universal Algebra, and
Computer Science, vol. 16, J. Czelakowski, Ed. Cham: Springer Nature, 2018,
pp. 203–220.'
ista: 'Kazda A, Kozik M, McKenzie R, Moore M. 2018.Absorption and directed Jónsson
terms. In: Don Pigozzi on Abstract Algebraic Logic, Universal Algebra, and Computer
Science. vol. 16, 203–220.'
mla: Kazda, Alexandr, et al. “Absorption and Directed Jónsson Terms.” Don Pigozzi
on Abstract Algebraic Logic, Universal Algebra, and Computer Science, edited
by J Czelakowski, vol. 16, Springer Nature, 2018, pp. 203–20, doi:10.1007/978-3-319-74772-9_7.
short: A. Kazda, M. Kozik, R. McKenzie, M. Moore, in:, J. Czelakowski (Ed.), Don
Pigozzi on Abstract Algebraic Logic, Universal Algebra, and Computer Science,
Springer Nature, Cham, 2018, pp. 203–220.
date_created: 2022-03-18T10:30:32Z
date_published: 2018-03-21T00:00:00Z
date_updated: 2023-09-05T15:37:18Z
day: '21'
department:
- _id: VlKo
doi: 10.1007/978-3-319-74772-9_7
editor:
- first_name: J
full_name: Czelakowski, J
last_name: Czelakowski
external_id:
arxiv:
- '1502.01072'
intvolume: ' 16'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://arxiv.org/abs/1502.01072
month: '03'
oa: 1
oa_version: Preprint
page: 203-220
place: Cham
publication: Don Pigozzi on Abstract Algebraic Logic, Universal Algebra, and Computer
Science
publication_identifier:
eisbn:
- '9783319747729'
eissn:
- 2211-2766
isbn:
- '9783319747712'
issn:
- 2211-2758
publication_status: published
publisher: Springer Nature
quality_controlled: '1'
scopus_import: '1'
series_title: OCTR
status: public
title: Absorption and directed Jónsson terms
type: book_chapter
user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1
volume: 16
year: '2018'
...
---
_id: '184'
abstract:
- lang: eng
text: We prove that for every d ≥ 2, deciding if a pure, d-dimensional, simplicial
complex is shellable is NP-hard, hence NP-complete. This resolves a question raised,
e.g., by Danaraj and Klee in 1978. Our reduction also yields that for every d
≥ 2 and k ≥ 0, deciding if a pure, d-dimensional, simplicial complex is k-decomposable
is NP-hard. For d ≥ 3, both problems remain NP-hard when restricted to contractible
pure d-dimensional complexes.
acknowledgement: 'Partially supported by the project EMBEDS II (CZ: 7AMB17FR029, FR:
38087RM) of Czech-French collaboration.'
alternative_title:
- Leibniz International Proceedings in Information, LIPIcs
author:
- first_name: Xavier
full_name: Goaoc, Xavier
last_name: Goaoc
- first_name: Pavel
full_name: Paták, Pavel
last_name: Paták
- 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: 'Goaoc X, Paták P, Patakova Z, Tancer M, Wagner U. Shellability is NP-complete.
In: Vol 99. Schloss Dagstuhl - Leibniz-Zentrum für Informatik; 2018:41:1-41:16.
doi:10.4230/LIPIcs.SoCG.2018.41'
apa: 'Goaoc, X., Paták, P., Patakova, Z., Tancer, M., & Wagner, U. (2018). Shellability
is NP-complete (Vol. 99, p. 41:1-41:16). Presented at the SoCG: Symposium on Computational
Geometry, Budapest, Hungary: Schloss Dagstuhl - Leibniz-Zentrum für Informatik.
https://doi.org/10.4230/LIPIcs.SoCG.2018.41'
chicago: Goaoc, Xavier, Pavel Paták, Zuzana Patakova, Martin Tancer, and Uli Wagner.
“Shellability Is NP-Complete,” 99:41:1-41:16. Schloss Dagstuhl - Leibniz-Zentrum
für Informatik, 2018. https://doi.org/10.4230/LIPIcs.SoCG.2018.41.
ieee: 'X. Goaoc, P. Paták, Z. Patakova, M. Tancer, and U. Wagner, “Shellability
is NP-complete,” presented at the SoCG: Symposium on Computational Geometry, Budapest,
Hungary, 2018, vol. 99, p. 41:1-41:16.'
ista: 'Goaoc X, Paták P, Patakova Z, Tancer M, Wagner U. 2018. Shellability is NP-complete.
SoCG: Symposium on Computational Geometry, Leibniz International Proceedings in
Information, LIPIcs, vol. 99, 41:1-41:16.'
mla: Goaoc, Xavier, et al. Shellability Is NP-Complete. Vol. 99, Schloss
Dagstuhl - Leibniz-Zentrum für Informatik, 2018, p. 41:1-41:16, doi:10.4230/LIPIcs.SoCG.2018.41.
short: X. Goaoc, P. Paták, Z. Patakova, M. Tancer, U. Wagner, in:, Schloss Dagstuhl
- Leibniz-Zentrum für Informatik, 2018, p. 41:1-41:16.
conference:
end_date: 2018-06-14
location: Budapest, Hungary
name: 'SoCG: Symposium on Computational Geometry'
start_date: 2018-06-11
date_created: 2018-12-11T11:45:04Z
date_published: 2018-06-11T00:00:00Z
date_updated: 2023-09-06T11:10:57Z
day: '11'
ddc:
- '516'
- '000'
department:
- _id: UlWa
doi: 10.4230/LIPIcs.SoCG.2018.41
file:
- access_level: open_access
checksum: d12bdd60f04a57307867704b5f930afd
content_type: application/pdf
creator: dernst
date_created: 2018-12-17T16:35:02Z
date_updated: 2020-07-14T12:45:18Z
file_id: '5725'
file_name: 2018_LIPIcs_Goaoc.pdf
file_size: 718414
relation: main_file
file_date_updated: 2020-07-14T12:45:18Z
has_accepted_license: '1'
intvolume: ' 99'
language:
- iso: eng
license: https://creativecommons.org/licenses/by/4.0/
month: '06'
oa: 1
oa_version: Published Version
page: 41:1 - 41:16
publication_status: published
publisher: Schloss Dagstuhl - Leibniz-Zentrum für Informatik
publist_id: '7736'
quality_controlled: '1'
related_material:
record:
- id: '7108'
relation: later_version
status: public
scopus_import: 1
status: public
title: Shellability is NP-complete
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: 99
year: '2018'
...
---
_id: '285'
abstract:
- lang: eng
text: In graph theory, as well as in 3-manifold topology, there exist several width-type
parameters to describe how "simple" or "thin" a given graph
or 3-manifold is. These parameters, such as pathwidth or treewidth for graphs,
or the concept of thin position for 3-manifolds, play an important role when studying
algorithmic problems; in particular, there is a variety of problems in computational
3-manifold topology - some of them known to be computationally hard in general
- that become solvable in polynomial time as soon as the dual graph of the input
triangulation has bounded treewidth. In view of these algorithmic results, it
is natural to ask whether every 3-manifold admits a triangulation of bounded treewidth.
We show that this is not the case, i.e., that there exists an infinite family
of closed 3-manifolds not admitting triangulations of bounded pathwidth or treewidth
(the latter implies the former, but we present two separate proofs). We derive
these results from work of Agol and of Scharlemann and Thompson, by exhibiting
explicit connections between the topology of a 3-manifold M on the one hand and
width-type parameters of the dual graphs of triangulations of M on the other hand,
answering a question that had been raised repeatedly by researchers in computational
3-manifold topology. In particular, we show that if a closed, orientable, irreducible,
non-Haken 3-manifold M has a triangulation of treewidth (resp. pathwidth) k then
the Heegaard genus of M is at most 48(k+1) (resp. 4(3k+1)).
acknowledgement: Research of the second author was supported by the Einstein Foundation
(project “Einstein Visiting Fellow Santos”) and by the Simons Foundation (“Simons
Visiting Professors” program).
alternative_title:
- LIPIcs
article_number: '46'
article_processing_charge: No
author:
- first_name: Kristóf
full_name: Huszár, Kristóf
id: 33C26278-F248-11E8-B48F-1D18A9856A87
last_name: Huszár
orcid: 0000-0002-5445-5057
- first_name: Jonathan
full_name: Spreer, Jonathan
last_name: Spreer
- first_name: Uli
full_name: Wagner, Uli
id: 36690CA2-F248-11E8-B48F-1D18A9856A87
last_name: Wagner
orcid: 0000-0002-1494-0568
citation:
ama: 'Huszár K, Spreer J, Wagner U. On the treewidth of triangulated 3-manifolds.
In: Vol 99. Schloss Dagstuhl - Leibniz-Zentrum für Informatik; 2018. doi:10.4230/LIPIcs.SoCG.2018.46'
apa: 'Huszár, K., Spreer, J., & Wagner, U. (2018). On the treewidth of triangulated
3-manifolds (Vol. 99). Presented at the SoCG: Symposium on Computational Geometry,
Budapest, Hungary: Schloss Dagstuhl - Leibniz-Zentrum für Informatik. https://doi.org/10.4230/LIPIcs.SoCG.2018.46'
chicago: Huszár, Kristóf, Jonathan Spreer, and Uli Wagner. “On the Treewidth of
Triangulated 3-Manifolds,” Vol. 99. Schloss Dagstuhl - Leibniz-Zentrum für Informatik,
2018. https://doi.org/10.4230/LIPIcs.SoCG.2018.46.
ieee: 'K. Huszár, J. Spreer, and U. Wagner, “On the treewidth of triangulated 3-manifolds,”
presented at the SoCG: Symposium on Computational Geometry, Budapest, Hungary,
2018, vol. 99.'
ista: 'Huszár K, Spreer J, Wagner U. 2018. On the treewidth of triangulated 3-manifolds.
SoCG: Symposium on Computational Geometry, LIPIcs, vol. 99, 46.'
mla: Huszár, Kristóf, et al. On the Treewidth of Triangulated 3-Manifolds.
Vol. 99, 46, Schloss Dagstuhl - Leibniz-Zentrum für Informatik, 2018, doi:10.4230/LIPIcs.SoCG.2018.46.
short: K. Huszár, J. Spreer, U. Wagner, in:, Schloss Dagstuhl - Leibniz-Zentrum
für Informatik, 2018.
conference:
end_date: 2018-06-14
location: Budapest, Hungary
name: 'SoCG: Symposium on Computational Geometry'
start_date: 2018-06-11
date_created: 2018-12-11T11:45:37Z
date_published: 2018-06-01T00:00:00Z
date_updated: 2023-09-06T11:13:41Z
day: '01'
ddc:
- '516'
- '000'
department:
- _id: UlWa
doi: 10.4230/LIPIcs.SoCG.2018.46
external_id:
arxiv:
- '1712.00434'
file:
- access_level: open_access
checksum: 530d084116778135d5bffaa317479cac
content_type: application/pdf
creator: dernst
date_created: 2018-12-17T15:32:38Z
date_updated: 2020-07-14T12:45:51Z
file_id: '5713'
file_name: 2018_LIPIcs_Huszar.pdf
file_size: 642522
relation: main_file
file_date_updated: 2020-07-14T12:45:51Z
has_accepted_license: '1'
intvolume: ' 99'
language:
- iso: eng
month: '06'
oa: 1
oa_version: Submitted Version
publication_identifier:
issn:
- '18688969'
publication_status: published
publisher: Schloss Dagstuhl - Leibniz-Zentrum für Informatik
publist_id: '7614'
quality_controlled: '1'
related_material:
record:
- id: '7093'
relation: later_version
status: public
scopus_import: 1
status: public
title: On the treewidth of triangulated 3-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: 99
year: '2018'
...