--- _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 relation: source_file - access_level: open_access 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' ...