--- _id: '7186' abstract: - lang: eng text: "Tissue morphogenesis in developmental or physiological processes is regulated by molecular\r\nand mechanical signals. While the molecular signaling cascades are increasingly well\r\ndescribed, the mechanical signals affecting tissue shape changes have only recently been\r\nstudied in greater detail. To gain more insight into the mechanochemical and biophysical\r\nbasis of an epithelial spreading process (epiboly) in early zebrafish development, we studied\r\ncell-cell junction formation and actomyosin network dynamics at the boundary between\r\nsurface layer epithelial cells (EVL) and the yolk syncytial layer (YSL). During zebrafish epiboly,\r\nthe cell mass sitting on top of the yolk cell spreads to engulf the yolk cell by the end of\r\ngastrulation. It has been previously shown that an actomyosin ring residing within the YSL\r\npulls on the EVL tissue through a cable-constriction and a flow-friction motor, thereby\r\ndragging the tissue vegetal wards. Pulling forces are likely transmitted from the YSL\r\nactomyosin ring to EVL cells; however, the nature and formation of the junctional structure\r\nmediating this process has not been well described so far. Therefore, our main aim was to\r\ndetermine the nature, dynamics and potential function of the EVL-YSL junction during this\r\nepithelial tissue spreading. Specifically, we show that the EVL-YSL junction is a\r\nmechanosensitive structure, predominantly made of tight junction (TJ) proteins. The process\r\nof TJ mechanosensation depends on the retrograde flow of non-junctional, phase-separated\r\nZonula Occludens-1 (ZO-1) protein clusters towards the EVL-YSL boundary. Interestingly, we\r\ncould demonstrate that ZO-1 is present in a non-junctional pool on the surface of the yolk\r\ncell, and ZO-1 undergoes a phase separation process that likely renders the protein\r\nresponsive to flows. These flows are directed towards the junction and mediate proper\r\ntension-dependent recruitment of ZO-1. Upon reaching the EVL-YSL junction ZO-1 gets\r\nincorporated into the junctional pool mediated through its direct actin-binding domain.\r\nWhen the non-junctional pool and/or ZO-1 direct actin binding is absent, TJs fail in their\r\nproper mechanosensitive responses resulting in slower tissue spreading. We could further\r\ndemonstrate that depletion of ZO proteins within the YSL results in diminished actomyosin\r\nring formation. This suggests that a mechanochemical feedback loop is at work during\r\nzebrafish epiboly: ZO proteins help in proper actomyosin ring formation and actomyosin\r\ncontractility and flows positively influence ZO-1 junctional recruitment. Finally, such a\r\nmesoscale polarization process mediated through the flow of phase-separated protein\r\nclusters might have implications for other processes such as immunological synapse\r\nformation, C. elegans zygote polarization and wound healing." acknowledged_ssus: - _id: Bio - _id: LifeSc - _id: EM-Fac - _id: SSU alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Cornelia full_name: Schwayer, Cornelia id: 3436488C-F248-11E8-B48F-1D18A9856A87 last_name: Schwayer orcid: 0000-0001-5130-2226 citation: ama: Schwayer C. Mechanosensation of tight junctions depends on ZO-1 phase separation and flow. 2019. doi:10.15479/AT:ISTA:7186 apa: Schwayer, C. (2019). Mechanosensation of tight junctions depends on ZO-1 phase separation and flow. Institute of Science and Technology Austria. https://doi.org/10.15479/AT:ISTA:7186 chicago: Schwayer, Cornelia. “Mechanosensation of Tight Junctions Depends on ZO-1 Phase Separation and Flow.” Institute of Science and Technology Austria, 2019. https://doi.org/10.15479/AT:ISTA:7186. ieee: C. Schwayer, “Mechanosensation of tight junctions depends on ZO-1 phase separation and flow,” Institute of Science and Technology Austria, 2019. ista: Schwayer C. 2019. Mechanosensation of tight junctions depends on ZO-1 phase separation and flow. Institute of Science and Technology Austria. mla: Schwayer, Cornelia. Mechanosensation of Tight Junctions Depends on ZO-1 Phase Separation and Flow. Institute of Science and Technology Austria, 2019, doi:10.15479/AT:ISTA:7186. short: C. Schwayer, Mechanosensation of Tight Junctions Depends on ZO-1 Phase Separation and Flow, Institute of Science and Technology Austria, 2019. date_created: 2019-12-16T14:26:14Z date_published: 2019-12-16T00:00:00Z date_updated: 2023-09-07T12:56:42Z day: '16' ddc: - '570' degree_awarded: PhD department: - _id: CaHe doi: 10.15479/AT:ISTA:7186 file: - access_level: closed checksum: 585583c1c875c5d9525703a539668a7c content_type: application/zip creator: cschwayer date_created: 2019-12-19T15:18:11Z date_updated: 2020-07-14T12:47:52Z file_id: '7194' file_name: DocumentSourceFiles.zip file_size: 19431292 relation: source_file - access_level: open_access checksum: 9b9b24351514948d27cec659e632e2cd content_type: application/pdf creator: cschwayer date_created: 2019-12-19T15:19:21Z date_updated: 2020-07-14T12:47:52Z file_id: '7195' file_name: Thesis_CS_final.pdf file_size: 19226428 relation: main_file file_date_updated: 2020-07-14T12:47:52Z has_accepted_license: '1' language: - iso: eng month: '12' oa: 1 oa_version: Published Version page: '107' publication_identifier: issn: - 2663-337X publication_status: published publisher: Institute of Science and Technology Austria related_material: record: - id: '1096' relation: dissertation_contains status: public - id: '7001' relation: part_of_dissertation status: public status: public supervisor: - first_name: Carl-Philipp J full_name: Heisenberg, Carl-Philipp J id: 39427864-F248-11E8-B48F-1D18A9856A87 last_name: Heisenberg orcid: 0000-0002-0912-4566 title: Mechanosensation of tight junctions depends on ZO-1 phase separation and flow type: dissertation user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1 year: '2019' ... --- _id: '6681' abstract: - lang: eng text: "The first part of the thesis considers the computational aspects of the homotopy groups πd(X) of a topological space X. It is well known that there is no algorithm to decide whether the fundamental group π1(X) of a given finite simplicial complex X is trivial. On the other hand, there are several algorithms that, given a finite simplicial complex X that is simply connected (i.e., with π1(X) trivial), compute the higher homotopy group πd(X) for any given d ≥ 2.\r\nHowever, these algorithms come with a caveat: They compute the isomorphism type of πd(X), d ≥ 2 as an abstract finitely generated abelian group given by generators and relations, but they work with very implicit representations of the elements of πd(X). We present an algorithm that, given a simply connected space X, computes πd(X) and represents its elements as simplicial maps from suitable triangulations of the d-sphere Sd to X. For fixed d, the algorithm runs in time exponential in size(X), the number of simplices of X. Moreover, we prove that this is optimal: For every fixed d ≥ 2,\r\nwe construct a family of simply connected spaces X such that for any simplicial map representing a generator of πd(X), the size of the triangulation of S d on which the map is defined, is exponential in size(X).\r\nIn the second part of the thesis, we prove that the following question is algorithmically undecidable for d < ⌊3(k+1)/2⌋, k ≥ 5 and (k, d) ̸= (5, 7), which covers essentially everything outside the meta-stable range: Given a finite simplicial complex K of dimension k, decide whether there exists a piecewise-linear (i.e., linear on an arbitrarily fine subdivision of K) embedding f : K ↪→ Rd of K into a d-dimensional Euclidean space." alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Stephan Y full_name: Zhechev, Stephan Y id: 3AA52972-F248-11E8-B48F-1D18A9856A87 last_name: Zhechev citation: ama: Zhechev SY. Algorithmic aspects of homotopy theory and embeddability. 2019. doi:10.15479/AT:ISTA:6681 apa: Zhechev, S. Y. (2019). Algorithmic aspects of homotopy theory and embeddability. Institute of Science and Technology Austria. https://doi.org/10.15479/AT:ISTA:6681 chicago: Zhechev, Stephan Y. “Algorithmic Aspects of Homotopy Theory and Embeddability.” Institute of Science and Technology Austria, 2019. https://doi.org/10.15479/AT:ISTA:6681. ieee: S. Y. Zhechev, “Algorithmic aspects of homotopy theory and embeddability,” Institute of Science and Technology Austria, 2019. ista: Zhechev SY. 2019. Algorithmic aspects of homotopy theory and embeddability. Institute of Science and Technology Austria. mla: Zhechev, Stephan Y. Algorithmic Aspects of Homotopy Theory and Embeddability. Institute of Science and Technology Austria, 2019, doi:10.15479/AT:ISTA:6681. short: S.Y. Zhechev, Algorithmic Aspects of Homotopy Theory and Embeddability, Institute of Science and Technology Austria, 2019. date_created: 2019-07-26T11:14:34Z date_published: 2019-08-08T00:00:00Z date_updated: 2023-09-07T13:10:36Z day: '08' ddc: - '514' degree_awarded: PhD department: - _id: UlWa doi: 10.15479/AT:ISTA:6681 file: - access_level: open_access checksum: 3231e7cbfca3b5687366f84f0a57a0c0 content_type: application/pdf creator: szhechev date_created: 2019-08-07T13:02:50Z date_updated: 2020-07-14T12:47:37Z file_id: '6771' file_name: Stephan_Zhechev_thesis.pdf file_size: 1464227 relation: main_file - access_level: closed checksum: 85d65eb27b4377a9e332ee37a70f08b6 content_type: application/octet-stream creator: szhechev date_created: 2019-08-07T13:03:22Z date_updated: 2020-07-14T12:47:37Z file_id: '6772' file_name: Stephan_Zhechev_thesis.tex file_size: 303988 relation: source_file - access_level: closed checksum: 86b374d264ca2dd53e712728e253ee75 content_type: application/zip creator: szhechev date_created: 2019-08-07T13:03:34Z date_updated: 2020-07-14T12:47:37Z file_id: '6773' file_name: supplementary_material.zip file_size: 1087004 relation: supplementary_material file_date_updated: 2020-07-14T12:47:37Z has_accepted_license: '1' language: - iso: eng license: https://creativecommons.org/licenses/by/4.0/ month: '08' oa: 1 oa_version: Published Version page: '104' publication_identifier: issn: - 2663-337X publication_status: published publisher: Institute of Science and Technology Austria related_material: record: - id: '6774' relation: part_of_dissertation status: public status: public supervisor: - first_name: Uli full_name: Wagner, Uli id: 36690CA2-F248-11E8-B48F-1D18A9856A87 last_name: Wagner orcid: 0000-0002-1494-0568 title: Algorithmic aspects of homotopy theory and embeddability 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: '2019' ... --- _id: '8182' abstract: - lang: eng text: "Suppose that $n\\neq p^k$ and $n\\neq 2p^k$ for all $k$ and all primes $p$. We prove that for any Hausdorff compactum $X$ with a free action of the symmetric group $\\mathfrak S_n$ there exists an $\\mathfrak S_n$-equivariant map $X \\to\r\n{\\mathbb R}^n$ whose image avoids the diagonal $\\{(x,x\\dots,x)\\in {\\mathbb R}^n|x\\in {\\mathbb R}\\}$.\r\n Previously, the special cases of this statement for certain $X$ were usually proved using the equivartiant obstruction theory. Such calculations are difficult and may become infeasible past the first (primary) obstruction. We\r\ntake a different approach which allows us to prove the vanishing of all obstructions simultaneously. The essential step in the proof is classifying the possible degrees of $\\mathfrak S_n$-equivariant maps from the boundary\r\n$\\partial\\Delta^{n-1}$ of $(n-1)$-simplex to itself. Existence of equivariant maps between spaces is important for many questions arising from discrete mathematics and geometry, such as Kneser's conjecture, the Square Peg conjecture, the Splitting Necklace problem, and the Topological Tverberg conjecture, etc. We demonstrate the utility of our result applying it to one such question, a specific instance of envy-free division problem." article_number: '1910.12628' article_processing_charge: No author: - first_name: Sergey full_name: Avvakumov, Sergey id: 3827DAC8-F248-11E8-B48F-1D18A9856A87 last_name: Avvakumov - first_name: Sergey full_name: Kudrya, Sergey id: ecf01965-d252-11ea-95a5-8ada5f6c6a67 last_name: Kudrya citation: ama: Avvakumov S, Kudrya S. Vanishing of all equivariant obstructions and the mapping degree. arXiv. apa: Avvakumov, S., & Kudrya, S. (n.d.). Vanishing of all equivariant obstructions and the mapping degree. arXiv. arXiv. chicago: Avvakumov, Sergey, and Sergey Kudrya. “Vanishing of All Equivariant Obstructions and the Mapping Degree.” ArXiv. arXiv, n.d. ieee: S. Avvakumov and S. Kudrya, “Vanishing of all equivariant obstructions and the mapping degree,” arXiv. arXiv. ista: Avvakumov S, Kudrya S. Vanishing of all equivariant obstructions and the mapping degree. arXiv, 1910.12628. mla: Avvakumov, Sergey, and Sergey Kudrya. “Vanishing of All Equivariant Obstructions and the Mapping Degree.” ArXiv, 1910.12628, arXiv. short: S. Avvakumov, S. Kudrya, ArXiv (n.d.). date_created: 2020-07-30T10:45:08Z date_published: 2019-10-28T00:00:00Z date_updated: 2023-09-07T13:12:17Z day: '28' department: - _id: UlWa external_id: arxiv: - '1910.12628' language: - iso: eng main_file_link: - open_access: '1' url: https://arxiv.org/abs/1910.12628 month: '10' oa: 1 oa_version: Preprint project: - _id: 26611F5C-B435-11E9-9278-68D0E5697425 call_identifier: FWF grant_number: P31312 name: Algorithms for Embeddings and Homotopy Theory publication: arXiv publication_status: submitted publisher: arXiv related_material: record: - id: '11446' relation: later_version status: public - id: '8156' relation: dissertation_contains status: public status: public title: Vanishing of all equivariant obstructions and the mapping degree type: preprint user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 year: '2019' ... --- _id: '8185' abstract: - lang: eng text: "In this paper we study envy-free division problems. The classical approach to some of such problems, used by David Gale, reduces to considering continuous maps of a simplex to itself and finding sufficient conditions when this map hits the center of the simplex. The mere continuity is not sufficient for such a conclusion, the usual assumption (for example, in the Knaster--Kuratowski--Mazurkiewicz and the Gale theorem) is a certain boundary condition.\r\n We follow Erel Segal-Halevi, Fr\\'ed\\'eric Meunier, and Shira Zerbib, and replace the boundary condition by another assumption, which has the economic meaning of possibility for a player to prefer an empty part in the segment\r\npartition problem. We solve the problem positively when $n$, the number of players that divide the segment, is a prime power, and we provide counterexamples for every $n$ which is not a prime power. We also provide counterexamples relevant to a wider class of fair or envy-free partition problems when $n$ is odd and not a prime power." article_number: '1907.11183' article_processing_charge: No author: - first_name: Sergey full_name: Avvakumov, Sergey id: 3827DAC8-F248-11E8-B48F-1D18A9856A87 last_name: Avvakumov - first_name: Roman full_name: Karasev, Roman last_name: Karasev citation: ama: Avvakumov S, Karasev R. Envy-free division using mapping degree. arXiv. doi:10.48550/arXiv.1907.11183 apa: Avvakumov, S., & Karasev, R. (n.d.). Envy-free division using mapping degree. arXiv. https://doi.org/10.48550/arXiv.1907.11183 chicago: Avvakumov, Sergey, and Roman Karasev. “Envy-Free Division Using Mapping Degree.” ArXiv, n.d. https://doi.org/10.48550/arXiv.1907.11183. ieee: S. Avvakumov and R. Karasev, “Envy-free division using mapping degree,” arXiv. . ista: Avvakumov S, Karasev R. Envy-free division using mapping degree. arXiv, 1907.11183. mla: Avvakumov, Sergey, and Roman Karasev. “Envy-Free Division Using Mapping Degree.” ArXiv, 1907.11183, doi:10.48550/arXiv.1907.11183. short: S. Avvakumov, R. Karasev, ArXiv (n.d.). date_created: 2020-07-30T10:45:51Z date_published: 2019-07-25T00:00:00Z date_updated: 2023-09-07T13:12:17Z day: '25' department: - _id: UlWa doi: 10.48550/arXiv.1907.11183 external_id: arxiv: - '1907.11183' language: - iso: eng main_file_link: - open_access: '1' url: https://arxiv.org/abs/1907.11183 month: '07' oa: 1 oa_version: Preprint project: - _id: 26611F5C-B435-11E9-9278-68D0E5697425 call_identifier: FWF grant_number: P31312 name: Algorithms for Embeddings and Homotopy Theory publication: arXiv publication_status: submitted related_material: link: - relation: later_version url: https://doi.org/10.1112/mtk.12059 record: - id: '8156' relation: dissertation_contains status: public status: public title: Envy-free division using mapping degree type: preprint user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 year: '2019' ... --- _id: '7524' abstract: - lang: eng text: "We prove a lower bound for the free energy (per unit volume) of the two-dimensional Bose gas in the thermodynamic limit. We show that the free energy at density $\\rho$ and inverse temperature $\\beta$ differs from the one of the non-interacting system by the correction term $4 \\pi \\rho^2 |\\ln a^2 \\rho|^{-1} (2 - [1 - \\beta_{\\mathrm{c}}/\\beta]_+^2)$. Here $a$ is the scattering length of the interaction potential, $[\\cdot]_+ = \\max\\{ 0, \\cdot \\}$ and $\\beta_{\\mathrm{c}}$ is the inverse Berezinskii--Kosterlitz--Thouless critical temperature for superfluidity. The result is valid in the dilute limit\r\n$a^2\\rho \\ll 1$ and if $\\beta \\rho \\gtrsim 1$." article_processing_charge: No author: - first_name: Andreas full_name: Deuchert, Andreas id: 4DA65CD0-F248-11E8-B48F-1D18A9856A87 last_name: Deuchert orcid: 0000-0003-3146-6746 - first_name: Simon full_name: Mayer, Simon id: 30C4630A-F248-11E8-B48F-1D18A9856A87 last_name: Mayer - first_name: Robert full_name: Seiringer, Robert id: 4AFD0470-F248-11E8-B48F-1D18A9856A87 last_name: Seiringer orcid: 0000-0002-6781-0521 citation: ama: Deuchert A, Mayer S, Seiringer R. The free energy of the two-dimensional dilute Bose gas. I. Lower bound. arXiv:191003372. apa: Deuchert, A., Mayer, S., & Seiringer, R. (n.d.). The free energy of the two-dimensional dilute Bose gas. I. Lower bound. arXiv:1910.03372. ArXiv. chicago: Deuchert, Andreas, Simon Mayer, and Robert Seiringer. “The Free Energy of the Two-Dimensional Dilute Bose Gas. I. Lower Bound.” ArXiv:1910.03372. ArXiv, n.d. ieee: A. Deuchert, S. Mayer, and R. Seiringer, “The free energy of the two-dimensional dilute Bose gas. I. Lower bound,” arXiv:1910.03372. ArXiv. ista: Deuchert A, Mayer S, Seiringer R. The free energy of the two-dimensional dilute Bose gas. I. Lower bound. arXiv:1910.03372, . mla: Deuchert, Andreas, et al. “The Free Energy of the Two-Dimensional Dilute Bose Gas. I. Lower Bound.” ArXiv:1910.03372, ArXiv. short: A. Deuchert, S. Mayer, R. Seiringer, ArXiv:1910.03372 (n.d.). date_created: 2020-02-26T08:46:40Z date_published: 2019-10-08T00:00:00Z date_updated: 2023-09-07T13:12:41Z day: '08' department: - _id: RoSe ec_funded: 1 language: - iso: eng main_file_link: - open_access: '1' url: https://arxiv.org/abs/1910.03372 month: '10' oa: 1 oa_version: Preprint page: '61' project: - _id: 25C6DC12-B435-11E9-9278-68D0E5697425 call_identifier: H2020 grant_number: '694227' name: Analysis of quantum many-body systems publication: arXiv:1910.03372 publication_status: draft publisher: ArXiv related_material: record: - id: '7790' relation: later_version status: public - id: '7514' relation: dissertation_contains status: public scopus_import: 1 status: public title: The free energy of the two-dimensional dilute Bose gas. I. Lower bound type: preprint user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 year: '2019' ... --- _id: '6608' abstract: - lang: eng text: We use the canonical bases produced by the tri-partition algorithm in (Edelsbrunner and Ölsböck, 2018) to open and close holes in a polyhedral complex, K. In a concrete application, we consider the Delaunay mosaic of a finite set, we let K be an Alpha complex, and we use the persistence diagram of the distance function to guide the hole opening and closing operations. The dependences between the holes define a partial order on the cells in K that characterizes what can and what cannot be constructed using the operations. The relations in this partial order reveal structural information about the underlying filtration of complexes beyond what is expressed by the persistence diagram. article_processing_charge: No author: - first_name: Herbert full_name: Edelsbrunner, Herbert id: 3FB178DA-F248-11E8-B48F-1D18A9856A87 last_name: Edelsbrunner orcid: 0000-0002-9823-6833 - first_name: Katharina full_name: Ölsböck, Katharina id: 4D4AA390-F248-11E8-B48F-1D18A9856A87 last_name: Ölsböck orcid: 0000-0002-4672-8297 citation: ama: Edelsbrunner H, Ölsböck K. Holes and dependences in an ordered complex. Computer Aided Geometric Design. 2019;73:1-15. doi:10.1016/j.cagd.2019.06.003 apa: Edelsbrunner, H., & Ölsböck, K. (2019). Holes and dependences in an ordered complex. Computer Aided Geometric Design. Elsevier. https://doi.org/10.1016/j.cagd.2019.06.003 chicago: Edelsbrunner, Herbert, and Katharina Ölsböck. “Holes and Dependences in an Ordered Complex.” Computer Aided Geometric Design. Elsevier, 2019. https://doi.org/10.1016/j.cagd.2019.06.003. ieee: H. Edelsbrunner and K. Ölsböck, “Holes and dependences in an ordered complex,” Computer Aided Geometric Design, vol. 73. Elsevier, pp. 1–15, 2019. ista: Edelsbrunner H, Ölsböck K. 2019. Holes and dependences in an ordered complex. Computer Aided Geometric Design. 73, 1–15. mla: Edelsbrunner, Herbert, and Katharina Ölsböck. “Holes and Dependences in an Ordered Complex.” Computer Aided Geometric Design, vol. 73, Elsevier, 2019, pp. 1–15, doi:10.1016/j.cagd.2019.06.003. short: H. Edelsbrunner, K. Ölsböck, Computer Aided Geometric Design 73 (2019) 1–15. date_created: 2019-07-07T21:59:20Z date_published: 2019-08-01T00:00:00Z date_updated: 2023-09-07T13:15:29Z day: '01' ddc: - '000' department: - _id: HeEd doi: 10.1016/j.cagd.2019.06.003 ec_funded: 1 external_id: isi: - '000485207800001' file: - access_level: open_access checksum: 7c99be505dc7533257d42eb1830cef04 content_type: application/pdf creator: kschuh date_created: 2019-07-08T15:24:26Z date_updated: 2020-07-14T12:47:34Z file_id: '6624' file_name: Elsevier_2019_Edelsbrunner.pdf file_size: 2665013 relation: main_file file_date_updated: 2020-07-14T12:47:34Z has_accepted_license: '1' intvolume: ' 73' isi: 1 language: - iso: eng license: https://creativecommons.org/licenses/by-nc-nd/4.0/ month: '08' oa: 1 oa_version: Published Version page: 1-15 project: - _id: 266A2E9E-B435-11E9-9278-68D0E5697425 call_identifier: H2020 grant_number: '788183' name: Alpha Shape Theory Extended - _id: 2561EBF4-B435-11E9-9278-68D0E5697425 call_identifier: FWF grant_number: I02979-N35 name: Persistence and stability of geometric complexes publication: Computer Aided Geometric Design publication_status: published publisher: Elsevier quality_controlled: '1' related_material: record: - id: '7460' relation: dissertation_contains status: public scopus_import: '1' status: public title: Holes and dependences in an ordered complex tmp: image: /images/cc_by_nc_nd.png legal_code_url: https://creativecommons.org/licenses/by-nc-nd/4.0/legalcode name: Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) short: CC BY-NC-ND (4.0) type: journal_article user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8 volume: 73 year: '2019' ... --- _id: '6677' abstract: - lang: eng text: "The Fiat-Shamir heuristic transforms a public-coin interactive proof into a non-interactive argument, by replacing the verifier with a cryptographic hash function that is applied to the protocol’s transcript. Constructing hash functions for which this transformation is sound is a central and long-standing open question in cryptography.\r\n\r\nWe show that solving the END−OF−METERED−LINE problem is no easier than breaking the soundness of the Fiat-Shamir transformation when applied to the sumcheck protocol. In particular, if the transformed protocol is sound, then any hard problem in #P gives rise to a hard distribution in the class CLS, which is contained in PPAD. Our result opens up the possibility of sampling moderately-sized games for which it is hard to find a Nash equilibrium, by reducing the inversion of appropriately chosen one-way functions to #SAT.\r\n\r\nOur main technical contribution is a stateful incrementally verifiable procedure that, given a SAT instance over n variables, counts the number of satisfying assignments. This is accomplished via an exponential sequence of small steps, each computable in time poly(n). Incremental verifiability means that each intermediate state includes a sumcheck-based proof of its correctness, and the proof can be updated and verified in time poly(n)." article_processing_charge: No author: - first_name: Arka Rai full_name: Choudhuri, Arka Rai last_name: Choudhuri - first_name: Pavel full_name: Hubáček, Pavel last_name: Hubáček - first_name: Chethan full_name: Kamath Hosdurg, Chethan id: 4BD3F30E-F248-11E8-B48F-1D18A9856A87 last_name: Kamath Hosdurg - first_name: Krzysztof Z full_name: Pietrzak, Krzysztof Z id: 3E04A7AA-F248-11E8-B48F-1D18A9856A87 last_name: Pietrzak orcid: 0000-0002-9139-1654 - first_name: Alon full_name: Rosen, Alon last_name: Rosen - first_name: Guy N. full_name: Rothblum, Guy N. last_name: Rothblum citation: ama: 'Choudhuri AR, Hubáček P, Kamath Hosdurg C, Pietrzak KZ, Rosen A, Rothblum GN. Finding a Nash equilibrium is no easier than breaking Fiat-Shamir. In: Proceedings of the 51st Annual ACM SIGACT Symposium on Theory of Computing  - STOC 2019. ACM Press; 2019:1103-1114. doi:10.1145/3313276.3316400' apa: 'Choudhuri, A. R., Hubáček, P., Kamath Hosdurg, C., Pietrzak, K. Z., Rosen, A., & Rothblum, G. N. (2019). Finding a Nash equilibrium is no easier than breaking Fiat-Shamir. In Proceedings of the 51st Annual ACM SIGACT Symposium on Theory of Computing  - STOC 2019 (pp. 1103–1114). Phoenix, AZ, United States: ACM Press. https://doi.org/10.1145/3313276.3316400' chicago: Choudhuri, Arka Rai, Pavel Hubáček, Chethan Kamath Hosdurg, Krzysztof Z Pietrzak, Alon Rosen, and Guy N. Rothblum. “Finding a Nash Equilibrium Is No Easier than Breaking Fiat-Shamir.” In Proceedings of the 51st Annual ACM SIGACT Symposium on Theory of Computing  - STOC 2019, 1103–14. ACM Press, 2019. https://doi.org/10.1145/3313276.3316400. ieee: A. R. Choudhuri, P. Hubáček, C. Kamath Hosdurg, K. Z. Pietrzak, A. Rosen, and G. N. Rothblum, “Finding a Nash equilibrium is no easier than breaking Fiat-Shamir,” in Proceedings of the 51st Annual ACM SIGACT Symposium on Theory of Computing  - STOC 2019, Phoenix, AZ, United States, 2019, pp. 1103–1114. ista: 'Choudhuri AR, Hubáček P, Kamath Hosdurg C, Pietrzak KZ, Rosen A, Rothblum GN. 2019. Finding a Nash equilibrium is no easier than breaking Fiat-Shamir. Proceedings of the 51st Annual ACM SIGACT Symposium on Theory of Computing  - STOC 2019. STOC: Symposium on Theory of Computing, 1103–1114.' mla: Choudhuri, Arka Rai, et al. “Finding a Nash Equilibrium Is No Easier than Breaking Fiat-Shamir.” Proceedings of the 51st Annual ACM SIGACT Symposium on Theory of Computing  - STOC 2019, ACM Press, 2019, pp. 1103–14, doi:10.1145/3313276.3316400. short: A.R. Choudhuri, P. Hubáček, C. Kamath Hosdurg, K.Z. Pietrzak, A. Rosen, G.N. Rothblum, in:, Proceedings of the 51st Annual ACM SIGACT Symposium on Theory of Computing  - STOC 2019, ACM Press, 2019, pp. 1103–1114. conference: end_date: 2019-06-26 location: Phoenix, AZ, United States name: 'STOC: Symposium on Theory of Computing' start_date: 2019-06-23 date_created: 2019-07-24T09:20:53Z date_published: 2019-06-01T00:00:00Z date_updated: 2023-09-07T13:15:55Z day: '01' department: - _id: KrPi doi: 10.1145/3313276.3316400 ec_funded: 1 external_id: isi: - '000523199100100' isi: 1 language: - iso: eng main_file_link: - open_access: '1' url: https://eprint.iacr.org/2019/549 month: '06' oa: 1 oa_version: Preprint page: 1103-1114 project: - _id: 258AA5B2-B435-11E9-9278-68D0E5697425 call_identifier: H2020 grant_number: '682815' name: Teaching Old Crypto New Tricks publication: Proceedings of the 51st Annual ACM SIGACT Symposium on Theory of Computing - STOC 2019 publication_identifier: isbn: - '9781450367059' publication_status: published publisher: ACM Press quality_controlled: '1' related_material: record: - id: '7896' relation: dissertation_contains status: public scopus_import: '1' status: public title: Finding a Nash equilibrium is no easier than breaking Fiat-Shamir type: conference user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8 year: '2019' ... --- _id: '5986' abstract: - lang: eng text: "Given a triangulation of a point set in the plane, a flip deletes an edge e whose removal leaves a convex quadrilateral, and replaces e by the opposite diagonal of the quadrilateral. It is well known that any triangulation of a point set can be reconfigured to any other triangulation by some sequence of flips. We explore this question in the setting where each edge of a triangulation has a label, and a flip transfers the label of the removed edge to the new edge. It is not true that every labelled triangulation of a point set can be reconfigured to every other labelled triangulation via a sequence of flips, but we characterize when this is possible. There is an obvious necessary condition: for each label l, if edge e has label l in the first triangulation and edge f has label l in the second triangulation, then there must be some sequence of flips that moves label l from e to f, ignoring all other labels. Bose, Lubiw, Pathak and Verdonschot formulated the Orbit Conjecture, which states that this necessary condition is also sufficient, i.e. that all labels can be simultaneously mapped to their destination if and only if each label individually can be mapped to its destination. We prove this conjecture. Furthermore, we give a polynomial-time algorithm (with \U0001D442(\U0001D45B8) being a crude bound on the run-time) to find a sequence of flips to reconfigure one labelled triangulation to another, if such a sequence exists, and we prove an upper bound of \U0001D442(\U0001D45B7) on the length of the flip sequence. Our proof uses the topological result that the sets of pairwise non-crossing edges on a planar point set form a simplicial complex that is homeomorphic to a high-dimensional ball (this follows from a result of Orden and Santos; we give a different proof based on a shelling argument). The dual cell complex of this simplicial ball, called the flip complex, has the usual flip graph as its 1-skeleton. We use properties of the 2-skeleton of the flip complex to prove the Orbit Conjecture." article_processing_charge: Yes (via OA deal) article_type: original author: - first_name: Anna full_name: Lubiw, Anna last_name: Lubiw - first_name: Zuzana full_name: Masárová, Zuzana id: 45CFE238-F248-11E8-B48F-1D18A9856A87 last_name: Masárová orcid: 0000-0002-6660-1322 - first_name: Uli full_name: Wagner, Uli id: 36690CA2-F248-11E8-B48F-1D18A9856A87 last_name: Wagner orcid: 0000-0002-1494-0568 citation: ama: Lubiw A, Masárová Z, Wagner U. A proof of the orbit conjecture for flipping edge-labelled triangulations. Discrete & Computational Geometry. 2019;61(4):880-898. doi:10.1007/s00454-018-0035-8 apa: Lubiw, A., Masárová, Z., & Wagner, U. (2019). A proof of the orbit conjecture for flipping edge-labelled triangulations. Discrete & Computational Geometry. Springer Nature. https://doi.org/10.1007/s00454-018-0035-8 chicago: Lubiw, Anna, Zuzana Masárová, and Uli Wagner. “A Proof of the Orbit Conjecture for Flipping Edge-Labelled Triangulations.” Discrete & Computational Geometry. Springer Nature, 2019. https://doi.org/10.1007/s00454-018-0035-8. ieee: A. Lubiw, Z. Masárová, and U. Wagner, “A proof of the orbit conjecture for flipping edge-labelled triangulations,” Discrete & Computational Geometry, vol. 61, no. 4. Springer Nature, pp. 880–898, 2019. ista: Lubiw A, Masárová Z, Wagner U. 2019. A proof of the orbit conjecture for flipping edge-labelled triangulations. Discrete & Computational Geometry. 61(4), 880–898. mla: Lubiw, Anna, et al. “A Proof of the Orbit Conjecture for Flipping Edge-Labelled Triangulations.” Discrete & Computational Geometry, vol. 61, no. 4, Springer Nature, 2019, pp. 880–98, doi:10.1007/s00454-018-0035-8. short: A. Lubiw, Z. Masárová, U. Wagner, Discrete & Computational Geometry 61 (2019) 880–898. date_created: 2019-02-14T11:54:08Z date_published: 2019-06-01T00:00:00Z date_updated: 2023-09-07T13:17:36Z day: '01' ddc: - '000' department: - _id: UlWa doi: 10.1007/s00454-018-0035-8 external_id: arxiv: - '1710.02741' isi: - '000466130000009' file: - access_level: open_access checksum: e1bff88f1d77001b53b78c485ce048d7 content_type: application/pdf creator: dernst date_created: 2019-02-14T11:57:22Z date_updated: 2020-07-14T12:47:14Z file_id: '5988' file_name: 2018_DiscreteGeometry_Lubiw.pdf file_size: 556276 relation: main_file file_date_updated: 2020-07-14T12:47:14Z has_accepted_license: '1' intvolume: ' 61' isi: 1 issue: '4' language: - iso: eng month: '06' oa: 1 oa_version: Published Version page: 880-898 project: - _id: B67AFEDC-15C9-11EA-A837-991A96BB2854 name: IST Austria Open Access Fund publication: Discrete & Computational Geometry publication_identifier: eissn: - 1432-0444 issn: - 0179-5376 publication_status: published publisher: Springer Nature quality_controlled: '1' related_material: record: - id: '683' relation: earlier_version status: public - id: '7944' relation: dissertation_contains status: public scopus_import: '1' status: public title: A proof of the orbit conjecture for flipping edge-labelled triangulations 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: journal_article user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1 volume: 61 year: '2019' ... --- _id: '5886' abstract: - lang: eng text: Problems involving quantum impurities, in which one or a few particles are interacting with a macroscopic environment, represent a pervasive paradigm, spanning across atomic, molecular, and condensed-matter physics. In this paper we introduce new variational approaches to quantum impurities and apply them to the Fröhlich polaron–a quasiparticle formed out of an electron (or other point-like impurity) in a polar medium, and to the angulon–a quasiparticle formed out of a rotating molecule in a bosonic bath. We benchmark these approaches against established theories, evaluating their accuracy as a function of the impurity-bath coupling. article_processing_charge: No author: - first_name: Xiang full_name: Li, Xiang id: 4B7E523C-F248-11E8-B48F-1D18A9856A87 last_name: Li - first_name: Giacomo full_name: Bighin, Giacomo id: 4CA96FD4-F248-11E8-B48F-1D18A9856A87 last_name: Bighin orcid: 0000-0001-8823-9777 - first_name: Enderalp full_name: Yakaboylu, Enderalp id: 38CB71F6-F248-11E8-B48F-1D18A9856A87 last_name: Yakaboylu orcid: 0000-0001-5973-0874 - first_name: Mikhail full_name: Lemeshko, Mikhail id: 37CB05FA-F248-11E8-B48F-1D18A9856A87 last_name: Lemeshko orcid: 0000-0002-6990-7802 citation: ama: 'Li X, Bighin G, Yakaboylu E, Lemeshko M. Variational approaches to quantum impurities: from the Fröhlich polaron to the angulon. Molecular Physics. 2019. doi:10.1080/00268976.2019.1567852' apa: 'Li, X., Bighin, G., Yakaboylu, E., & Lemeshko, M. (2019). Variational approaches to quantum impurities: from the Fröhlich polaron to the angulon. Molecular Physics. Taylor and Francis. https://doi.org/10.1080/00268976.2019.1567852' chicago: 'Li, Xiang, Giacomo Bighin, Enderalp Yakaboylu, and Mikhail Lemeshko. “Variational Approaches to Quantum Impurities: From the Fröhlich Polaron to the Angulon.” Molecular Physics. Taylor and Francis, 2019. https://doi.org/10.1080/00268976.2019.1567852.' ieee: 'X. Li, G. Bighin, E. Yakaboylu, and M. Lemeshko, “Variational approaches to quantum impurities: from the Fröhlich polaron to the angulon,” Molecular Physics. Taylor and Francis, 2019.' ista: 'Li X, Bighin G, Yakaboylu E, Lemeshko M. 2019. Variational approaches to quantum impurities: from the Fröhlich polaron to the angulon. Molecular Physics.' mla: 'Li, Xiang, et al. “Variational Approaches to Quantum Impurities: From the Fröhlich Polaron to the Angulon.” Molecular Physics, Taylor and Francis, 2019, doi:10.1080/00268976.2019.1567852.' short: X. Li, G. Bighin, E. Yakaboylu, M. Lemeshko, Molecular Physics (2019). date_created: 2019-01-27T22:59:10Z date_published: 2019-01-18T00:00:00Z date_updated: 2023-09-07T13:16:42Z day: '18' ddc: - '530' department: - _id: MiLe doi: 10.1080/00268976.2019.1567852 ec_funded: 1 external_id: isi: - '000474641400008' file: - access_level: open_access checksum: 178964744b636a6f036372f4f090a657 content_type: application/pdf creator: dernst date_created: 2019-01-29T08:32:57Z date_updated: 2020-07-14T12:47:13Z file_id: '5896' file_name: 2019_MolecularPhysics_Li.pdf file_size: 1309966 relation: main_file file_date_updated: 2020-07-14T12:47:13Z has_accepted_license: '1' isi: 1 language: - iso: eng month: '01' oa: 1 oa_version: Published Version project: - _id: 26031614-B435-11E9-9278-68D0E5697425 call_identifier: FWF grant_number: P29902 name: Quantum rotations in the presence of a many-body environment - _id: 25681D80-B435-11E9-9278-68D0E5697425 call_identifier: FP7 grant_number: '291734' name: International IST Postdoc Fellowship Programme publication: Molecular Physics publication_identifier: issn: - '00268976' publication_status: published publisher: Taylor and Francis quality_controlled: '1' related_material: record: - id: '8958' relation: dissertation_contains status: public scopus_import: '1' status: public title: 'Variational approaches to quantum impurities: from the Fröhlich polaron to the angulon' 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: journal_article user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8 year: '2019' ... --- _id: '6556' abstract: - lang: eng text: 'Motivated by fixed-parameter tractable (FPT) problems in computational topology, we consider the treewidth tw(M) of a compact, connected 3-manifold M, defined to be the minimum treewidth of the face pairing graph of any triangulation T of M. In this setting the relationship between the topology of a 3-manifold and its treewidth is of particular interest. First, as a corollary of work of Jaco and Rubinstein, we prove that for any closed, orientable 3-manifold M the treewidth tw(M) is at most 4g(M)-2, where g(M) denotes Heegaard genus of M. In combination with our earlier work with Wagner, this yields that for non-Haken manifolds the Heegaard genus and the treewidth are within a constant factor. Second, we characterize all 3-manifolds of treewidth one: These are precisely the lens spaces and a single other Seifert fibered space. Furthermore, we show that all remaining orientable Seifert fibered spaces over the 2-sphere or a non-orientable surface have treewidth two. In particular, for every spherical 3-manifold we exhibit a triangulation of treewidth at most two. Our results further validate the parameter of treewidth (and other related parameters such as cutwidth or congestion) to be useful for topological computing, and also shed more light on the scope of existing FPT-algorithms in the field.' alternative_title: - LIPIcs 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 citation: ama: 'Huszár K, Spreer J. 3-manifold triangulations with small treewidth. In: 35th International Symposium on Computational Geometry. Vol 129. Schloss Dagstuhl - Leibniz-Zentrum für Informatik; 2019:44:1-44:20. doi:10.4230/LIPIcs.SoCG.2019.44' apa: 'Huszár, K., & Spreer, J. (2019). 3-manifold triangulations with small treewidth. In 35th International Symposium on Computational Geometry (Vol. 129, p. 44:1-44:20). Portland, Oregon, United States: Schloss Dagstuhl - Leibniz-Zentrum für Informatik. https://doi.org/10.4230/LIPIcs.SoCG.2019.44' chicago: Huszár, Kristóf, and Jonathan Spreer. “3-Manifold Triangulations with Small Treewidth.” In 35th International Symposium on Computational Geometry, 129:44:1-44:20. Schloss Dagstuhl - Leibniz-Zentrum für Informatik, 2019. https://doi.org/10.4230/LIPIcs.SoCG.2019.44. ieee: K. Huszár and J. Spreer, “3-manifold triangulations with small treewidth,” in 35th International Symposium on Computational Geometry, Portland, Oregon, United States, 2019, vol. 129, p. 44:1-44:20. ista: 'Huszár K, Spreer J. 2019. 3-manifold triangulations with small treewidth. 35th International Symposium on Computational Geometry. SoCG: Symposium on Computational Geometry, LIPIcs, vol. 129, 44:1-44:20.' mla: Huszár, Kristóf, and Jonathan Spreer. “3-Manifold Triangulations with Small Treewidth.” 35th International Symposium on Computational Geometry, vol. 129, Schloss Dagstuhl - Leibniz-Zentrum für Informatik, 2019, p. 44:1-44:20, doi:10.4230/LIPIcs.SoCG.2019.44. short: K. Huszár, J. Spreer, in:, 35th International Symposium on Computational Geometry, Schloss Dagstuhl - Leibniz-Zentrum für Informatik, 2019, p. 44:1-44:20. conference: end_date: 2019-06-21 location: Portland, Oregon, United States name: 'SoCG: Symposium on Computational Geometry' start_date: 2019-06-18 date_created: 2019-06-11T20:09:57Z date_published: 2019-06-01T00:00:00Z date_updated: 2023-09-07T13:18:26Z day: '01' ddc: - '516' department: - _id: UlWa doi: 10.4230/LIPIcs.SoCG.2019.44 external_id: arxiv: - '1812.05528' file: - access_level: open_access checksum: 29d18c435368468aa85823dabb157e43 content_type: application/pdf creator: kschuh date_created: 2019-06-12T06:45:33Z date_updated: 2020-07-14T12:47:33Z file_id: '6557' file_name: 2019_LIPIcs-Huszar.pdf file_size: 905885 relation: main_file file_date_updated: 2020-07-14T12:47:33Z has_accepted_license: '1' intvolume: ' 129' keyword: - computational 3-manifold topology - fixed-parameter tractability - layered triangulations - structural graph theory - treewidth - cutwidth - Heegaard genus language: - iso: eng month: '06' oa: 1 oa_version: Published Version page: 44:1-44:20 publication: 35th International Symposium on Computational Geometry publication_identifier: isbn: - 978-3-95977-104-7 issn: - 1868-8969 publication_status: published publisher: Schloss Dagstuhl - Leibniz-Zentrum für Informatik quality_controlled: '1' related_material: record: - id: '8032' relation: part_of_dissertation status: public scopus_import: '1' status: public title: 3-manifold triangulations with small treewidth 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: 129 year: '2019' ...