---
_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
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'
...
---
_id: '13059'
abstract:
- lang: eng
text: "This dataset contains a GitHub repository containing all the data, analysis,
Nextflow workflows and Jupyter notebooks to replicate the manuscript titled \"Fast
and accurate large multiple sequence alignments with a root-to-leaf regressive
method\".\r\nIt also contains the Multiple Sequence Alignments (MSAs) generated
and well as the main figures and tables from the manuscript.\r\nThe repository
is also available at GitHub (https://github.com/cbcrg/dpa-analysis) release `v1.2`.\r\nFor
details on how to use the regressive alignment algorithm, see the T-Coffee software
suite (https://github.com/cbcrg/tcoffee)."
article_processing_charge: No
author:
- first_name: Edgar
full_name: Garriga, Edgar
last_name: Garriga
- first_name: Paolo
full_name: di Tommaso, Paolo
last_name: di Tommaso
- first_name: Cedrik
full_name: Magis, Cedrik
last_name: Magis
- first_name: Ionas
full_name: Erb, Ionas
last_name: Erb
- first_name: Leila
full_name: Mansouri, Leila
last_name: Mansouri
- first_name: Athanasios
full_name: Baltzis, Athanasios
last_name: Baltzis
- first_name: Hafid
full_name: Laayouni, Hafid
last_name: Laayouni
- first_name: Fyodor
full_name: Kondrashov, Fyodor
id: 44FDEF62-F248-11E8-B48F-1D18A9856A87
last_name: Kondrashov
orcid: 0000-0001-8243-4694
- first_name: Evan
full_name: Floden, Evan
last_name: Floden
- first_name: Cedric
full_name: Notredame, Cedric
last_name: Notredame
citation:
ama: Garriga E, di Tommaso P, Magis C, et al. Fast and accurate large multiple sequence
alignments with a root-to-leaf regressive method. 2018. doi:10.5281/ZENODO.2025846
apa: Garriga, E., di Tommaso, P., Magis, C., Erb, I., Mansouri, L., Baltzis, A.,
… Notredame, C. (2018). Fast and accurate large multiple sequence alignments with
a root-to-leaf regressive method. Zenodo. https://doi.org/10.5281/ZENODO.2025846
chicago: Garriga, Edgar, Paolo di Tommaso, Cedrik Magis, Ionas Erb, Leila Mansouri,
Athanasios Baltzis, Hafid Laayouni, Fyodor Kondrashov, Evan Floden, and Cedric
Notredame. “Fast and Accurate Large Multiple Sequence Alignments with a Root-to-Leaf
Regressive Method.” Zenodo, 2018. https://doi.org/10.5281/ZENODO.2025846.
ieee: E. Garriga et al., “Fast and accurate large multiple sequence alignments
with a root-to-leaf regressive method.” Zenodo, 2018.
ista: Garriga E, di Tommaso P, Magis C, Erb I, Mansouri L, Baltzis A, Laayouni H,
Kondrashov F, Floden E, Notredame C. 2018. Fast and accurate large multiple sequence
alignments with a root-to-leaf regressive method, Zenodo, 10.5281/ZENODO.2025846.
mla: Garriga, Edgar, et al. Fast and Accurate Large Multiple Sequence Alignments
with a Root-to-Leaf Regressive Method. Zenodo, 2018, doi:10.5281/ZENODO.2025846.
short: E. Garriga, P. di Tommaso, C. Magis, I. Erb, L. Mansouri, A. Baltzis, H.
Laayouni, F. Kondrashov, E. Floden, C. Notredame, (2018).
date_created: 2023-05-23T16:08:20Z
date_published: 2018-12-07T00:00:00Z
date_updated: 2023-09-06T14:32:51Z
day: '07'
ddc:
- '570'
department:
- _id: FyKo
doi: 10.5281/ZENODO.2025846
main_file_link:
- open_access: '1'
url: https://doi.org/10.5281/zenodo.3271452
month: '12'
oa: 1
oa_version: Published Version
publisher: Zenodo
related_material:
record:
- id: '7181'
relation: used_in_publication
status: public
status: public
title: Fast and accurate large multiple sequence alignments with a root-to-leaf regressive
method
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: research_data_reference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
year: '2018'
...
---
_id: '49'
abstract:
- lang: eng
text: Nowadays, quantum computation is receiving more and more attention as an alternative
to the classical way of computing. For realizing a quantum computer, different
devices are investigated as potential quantum bits. In this thesis, the focus
is on Ge hut wires, which turned out to be promising candidates for implementing
hole spin quantum bits. The advantages of Ge as a material system are the low
hyperfine interaction for holes and the strong spin orbit coupling, as well as
the compatibility with the highly developed CMOS processes in industry. In addition,
Ge can also be isotopically purified which is expected to boost the spin coherence
times. The strong spin orbit interaction for holes in Ge on the one hand enables
the full electrical control of the quantum bit and on the other hand should allow
short spin manipulation times. Starting with a bare Si wafer, this work covers
the entire process reaching from growth over the fabrication and characterization
of hut wire devices up to the demonstration of hole spin resonance. From experiments
with single quantum dots, a large g-factor anisotropy between the in-plane and
the out-of-plane direction was found. A comparison to a theoretical model unveiled
the heavy-hole character of the lowest energy states. The second part of the thesis
addresses double quantum dot devices, which were realized by adding two gate electrodes
to a hut wire. In such devices, Pauli spin blockade was observed, which can serve
as a read-out mechanism for spin quantum bits. Applying oscillating electric fields
in spin blockade allowed the demonstration of continuous spin rotations and the
extraction of a lower bound for the spin dephasing time. Despite the strong spin
orbit coupling in Ge, the obtained value for the dephasing time is comparable
to what has been recently reported for holes in Si. All in all, the presented
results point out the high potential of Ge hut wires as a platform for long-lived,
fast and fully electrically tunable hole spin quantum bits.
alternative_title:
- ISTA Thesis
article_processing_charge: No
author:
- first_name: Hannes
full_name: Watzinger, Hannes
id: 35DF8E50-F248-11E8-B48F-1D18A9856A87
last_name: Watzinger
citation:
ama: Watzinger H. Ge hut wires - from growth to hole spin resonance. 2018. doi:10.15479/AT:ISTA:th_1033
apa: Watzinger, H. (2018). Ge hut wires - from growth to hole spin resonance.
Institute of Science and Technology Austria. https://doi.org/10.15479/AT:ISTA:th_1033
chicago: Watzinger, Hannes. “Ge Hut Wires - from Growth to Hole Spin Resonance.”
Institute of Science and Technology Austria, 2018. https://doi.org/10.15479/AT:ISTA:th_1033.
ieee: H. Watzinger, “Ge hut wires - from growth to hole spin resonance,” Institute
of Science and Technology Austria, 2018.
ista: Watzinger H. 2018. Ge hut wires - from growth to hole spin resonance. Institute
of Science and Technology Austria.
mla: Watzinger, Hannes. Ge Hut Wires - from Growth to Hole Spin Resonance.
Institute of Science and Technology Austria, 2018, doi:10.15479/AT:ISTA:th_1033.
short: H. Watzinger, Ge Hut Wires - from Growth to Hole Spin Resonance, Institute
of Science and Technology Austria, 2018.
date_created: 2018-12-11T11:44:21Z
date_published: 2018-07-30T00:00:00Z
date_updated: 2023-09-07T12:27:43Z
day: '30'
ddc:
- '530'
degree_awarded: PhD
department:
- _id: GeKa
doi: 10.15479/AT:ISTA:th_1033
file:
- access_level: open_access
checksum: b653b5216251f938ddbeafd1de88667c
content_type: application/pdf
creator: dernst
date_created: 2019-04-09T07:13:28Z
date_updated: 2020-07-14T12:46:35Z
file_id: '6249'
file_name: 2018_Thesis_Watzinger.pdf
file_size: 85539748
relation: main_file
- access_level: closed
checksum: 39bcf8de7ac5b1bb516b11ce2f966785
content_type: application/zip
creator: dernst
date_created: 2019-04-09T07:13:27Z
date_updated: 2020-07-14T12:46:35Z
file_id: '6250'
file_name: 2018_Thesis_Watzinger_source.zip
file_size: 21830697
relation: source_file
file_date_updated: 2020-07-14T12:46:35Z
has_accepted_license: '1'
language:
- iso: eng
month: '07'
oa: 1
oa_version: Published Version
page: '77'
publication_identifier:
issn:
- 2663-337X
publication_status: published
publisher: Institute of Science and Technology Austria
publist_id: '8005'
pubrep_id: '1033'
status: public
supervisor:
- first_name: Georgios
full_name: Katsaros, Georgios
id: 38DB5788-F248-11E8-B48F-1D18A9856A87
last_name: Katsaros
orcid: 0000-0001-8342-202X
title: Ge hut wires - from growth to hole spin resonance
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: c635000d-4b10-11ee-a964-aac5a93f6ac1
year: '2018'
...
---
_id: '201'
abstract:
- lang: eng
text: 'We describe arrangements of three-dimensional spheres from a geometrical
and topological point of view. Real data (fitting this setup) often consist of
soft spheres which show certain degree of deformation while strongly packing against
each other. In this context, we answer the following questions: If we model a
soft packing of spheres by hard spheres that are allowed to overlap, can we measure
the volume in the overlapped areas? Can we be more specific about the overlap
volume, i.e. quantify how much volume is there covered exactly twice, three times,
or k times? What would be a good optimization criteria that rule the arrangement
of soft spheres while making a good use of the available space? Fixing a particular
criterion, what would be the optimal sphere configuration? The first result of
this thesis are short formulas for the computation of volumes covered by at least
k of the balls. The formulas exploit information contained in the order-k Voronoi
diagrams and its closely related Level-k complex. The used complexes lead to a
natural generalization into poset diagrams, a theoretical formalism that contains
the order-k and degree-k diagrams as special cases. In parallel, we define different
criteria to determine what could be considered an optimal arrangement from a geometrical
point of view. Fixing a criterion, we find optimal soft packing configurations
in 2D and 3D where the ball centers lie on a lattice. As a last step, we use tools
from computational topology on real physical data, to show the potentials of higher-order
diagrams in the description of melting crystals. The results of the experiments
leaves us with an open window to apply the theories developed in this thesis in
real applications.'
alternative_title:
- ISTA Thesis
article_processing_charge: No
author:
- first_name: Mabel
full_name: Iglesias Ham, Mabel
id: 41B58C0C-F248-11E8-B48F-1D18A9856A87
last_name: Iglesias Ham
citation:
ama: Iglesias Ham M. Multiple covers with balls. 2018. doi:10.15479/AT:ISTA:th_1026
apa: Iglesias Ham, M. (2018). Multiple covers with balls. Institute of Science
and Technology Austria. https://doi.org/10.15479/AT:ISTA:th_1026
chicago: Iglesias Ham, Mabel. “Multiple Covers with Balls.” Institute of Science
and Technology Austria, 2018. https://doi.org/10.15479/AT:ISTA:th_1026.
ieee: M. Iglesias Ham, “Multiple covers with balls,” Institute of Science and Technology
Austria, 2018.
ista: Iglesias Ham M. 2018. Multiple covers with balls. Institute of Science and
Technology Austria.
mla: Iglesias Ham, Mabel. Multiple Covers with Balls. Institute of Science
and Technology Austria, 2018, doi:10.15479/AT:ISTA:th_1026.
short: M. Iglesias Ham, Multiple Covers with Balls, Institute of Science and Technology
Austria, 2018.
date_created: 2018-12-11T11:45:10Z
date_published: 2018-06-11T00:00:00Z
date_updated: 2023-09-07T12:25:32Z
day: '11'
ddc:
- '514'
- '516'
degree_awarded: PhD
department:
- _id: HeEd
doi: 10.15479/AT:ISTA:th_1026
file:
- access_level: closed
checksum: dd699303623e96d1478a6ae07210dd05
content_type: application/zip
creator: kschuh
date_created: 2019-02-05T07:43:31Z
date_updated: 2020-07-14T12:45:24Z
file_id: '5918'
file_name: IST-2018-1025-v2+5_ist-thesis-iglesias-11June2018(1).zip
file_size: 11827713
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checksum: ba163849a190d2b41d66fef0e4983294
content_type: application/pdf
creator: kschuh
date_created: 2019-02-05T07:43:45Z
date_updated: 2020-07-14T12:45:24Z
file_id: '5919'
file_name: IST-2018-1025-v2+4_ThesisIglesiasFinal11June2018.pdf
file_size: 4783846
relation: main_file
file_date_updated: 2020-07-14T12:45:24Z
has_accepted_license: '1'
language:
- iso: eng
month: '06'
oa: 1
oa_version: Published Version
page: '171'
publication_identifier:
issn:
- 2663-337X
publication_status: published
publisher: Institute of Science and Technology Austria
publist_id: '7712'
pubrep_id: '1026'
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: Multiple covers with balls
type: dissertation
user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1
year: '2018'
...