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YOKOYAMA Tomoo
Mathematics, Electronics and Informatics DivisionProfessor
Mathematics

Researcher information

■ Degree
  • PhD (Mathematical Sciences), The University of Tokyo
■ Field Of Study
  • Natural sciences, Geometry
■ Career
  • Apr. 2021 - Mar. 2023, Gifu University
  • Sep. 2013 - Mar. 2021, KYOTO UNIVERSITY OF EDUCATION, Mathematics, Associate Professor
  • Oct. 2016 - Mar. 2020, Japan Science and Technology Agency
■ Award
  • JSIAM Paper Awards 2020, The Japan Society for Industrial and Applied Mathematics

Performance information

■ Paper
  • Morse hyper-graphs of topological spaces and decompositions
    Tomoo Yokoyama
    Journal of Applied and Computational Topology, Volume:9, Number:1, Mar. 2025
    Springer Science and Business Media LLC, Scientific journal
    DOI:https://doi.org/10.1007/s41468-025-00206-y
    DOI ID:10.1007/s41468-025-00206-y, ISSN:2367-1726, eISSN:2367-1734
  • Topological characterizations of Hamiltonian flows on unbounded surfaces               
    Tomoo Yokoyama
    Colloquium Mathematicum, Volume:177, Number:1-2, First page:135, Last page:160, Jan. 2025
    Institute of Mathematics, Polish Academy of Sciences, Scientific journal
    DOI:https://doi.org/10.4064/cm8915-1-2025
    DOI ID:10.4064/cm8915-1-2025, ISSN:0010-1354, eISSN:1730-6302
  • A Poincaré–Bendixson theorem for flows with arbitrarily many singular points               
    Tomoo Yokoyama
    Studia Mathematica, Volume:278, Number:2, First page:99, Last page:172, Nov. 2024, [Reviewed]
    Institute of Mathematics, Polish Academy of Sciences, Scientific journal
    DOI:https://doi.org/10.4064/sm230506-9-9
    DOI ID:10.4064/sm230506-9-9, ISSN:0039-3223, eISSN:1730-6337
  • Topological characterizations of recurrence, Poisson stability, and isometric property of flows on surfaces
    Tomoo Yokoyama
    Israel Journal of Mathematics, Volume:261, Number:2, First page:951, Last page:975, Dec. 2023, [Reviewed]
    Springer Science and Business Media LLC, Scientific journal
    DOI:https://doi.org/10.1007/s11856-023-2601-x
    DOI ID:10.1007/s11856-023-2601-x, ISSN:0021-2172, eISSN:1565-8511
  • Dependency of the positive and negative long-time behaviors of flows on surfaces               
    Tomoo Yokoyama
    Journal of Differential Equations, Volume:368, First page:376, Last page:393, Sep. 2023, [Reviewed]
    Elsevier BV, Scientific journal
    DOI:https://doi.org/10.1016/j.jde.2023.06.008
    DOI ID:10.1016/j.jde.2023.06.008, ISSN:0022-0396
  • Refinements of topological invariants of flows               
    Tomoo Yokoyama
    Discrete and Continuous Dynamical Systems, Volume:42, Number:5, First page:2295, Last page:2295, Nov. 2022, [Reviewed]

    <p style='text-indent:20px;'>We construct topological invariants, called abstract weak orbit spaces, of flows and homeomorphisms on topological spaces. In particular, the abstract weak orbit spaces of flows on topological spaces are refinements of Morse graphs of flows on compact metric spaces, Reeb graphs of Hamiltonian flows with finitely many singular points on surfaces, and the CW decompositions which consist of the unstable manifolds of singular points for Morse flows on closed manifolds. Though the CW decomposition of a Morse flow is finite, the intersection of the unstable manifold and the stable manifold of closed orbits need not consist of finitely many connected components. Therefore we study the finiteness. Moreover, we consider when the time-one map reconstructs the topology of the original flow. We show that the orbit space of a Hamiltonian flow with finitely many singular points on a compact surface is homeomorphic to the abstract weak orbit space of the time-one map by taking an arbitrarily small reparametrization and that the abstract weak orbit spaces of a Morse flow on a compact manifold and the time-one map are homeomorphic. In addition, we state examples whose Morse graphs are singletons but whose abstract weak orbit spaces are not singletons.</p>


    American Institute of Mathematical Sciences (AIMS), Scientific journal
    DOI:https://doi.org/10.3934/dcds.2021191
    DOI ID:10.3934/dcds.2021191, ISSN:1078-0947, eISSN:1553-5231
  • Topological characterizations of Morse-Smale flows on surfaces and generic non-Morse-Smale flows               
    Vladislav Kibkalo; Tomoo Yokoyama
    Discrete and Continuous Dynamical Systems, Volume:42, Number:10, First page:4787, Last page:4787, Oct. 2022, [Reviewed]

    <p style='text-indent:20px;'>It is known that <inline-formula><tex-math id="M1">\begin{document}$ C^r $\end{document}</tex-math></inline-formula> Morse-Smale vector fields form an open dense subset in the space of vector fields on orientable closed surfaces and are structurally stable for any <inline-formula><tex-math id="M2">\begin{document}$ r \in \mathbb{Z}_{\geq 1} $\end{document}</tex-math></inline-formula>. In particular, <inline-formula><tex-math id="M3">\begin{document}$ C^r $\end{document}</tex-math></inline-formula> Morse vector fields (i.e. Morse-Smale vector fields without limit cycles) form an open dense subset in the space of <inline-formula><tex-math id="M4">\begin{document}$ C^r $\end{document}</tex-math></inline-formula> gradient vector fields on orientable closed surfaces and are structurally stable. Therefore generic time evaluations of gradient flows on orientable closed surfaces (e.g. solutions of differential equations) are described by alternating sequences of Morse flows and instantaneous non-Morse gradient flows. To illustrate the generic transitions (e.g. bifurcations of singular points, transitions via heteroclinic separatrices), we characterize and list all generic non-Morse gradient flows. To construct such characterizations, we characterize isolated singular points of gradient flows on surfaces. In fact, such a singular point is a non-trivial finitely sectored singular point without elliptic sectors. Moreover, considering Morse-Smale flows as "generic gradient flows with limit cycles", we characterize and list all generic non-Morse-Smale flows.</p>


    American Institute of Mathematical Sciences (AIMS), Scientific journal
    DOI:https://doi.org/10.3934/dcds.2022072
    DOI ID:10.3934/dcds.2022072, ISSN:1078-0947, eISSN:1553-5231
  • Discrete representations of orbit structures of flows for topological data analysis
    Takashi Sakajo; Tomoo Yokoyama
    Discrete Mathematics, Algorithms and Applications, Sep. 2022, [Reviewed]
    This paper shows that the topological structures of particle orbits generated by a generic class of vector fields on spherical surfaces, called the flow of finite type, are in one-to-one correspondence with discrete structures such as trees/graphs and sequences of letters. The flow of finite type is an extension of structurally stable Hamiltonian vector fields, which appear in many theoretical and numerical investigations of two-dimensional (2D) incompressible fluid flows. Moreover, it contains compressible 2D vector fields such as the Morse–Smale vector fields and the projection of 3D vector fields onto 2D sections. The discrete representation is not only a simple symbolic identifier for the topological structure of complex flows, but it also gives rise to a new methodology of topological data analysis for flows when applied to data brought by measurements, experiments, and numerical simulations of complex flows. As a proof of concept, we provide some applications of the representation theory to 2D compressible vector fields and a 3D vector field arising in an industrial problem.
    World Scientific Pub Co Pte Ltd, Scientific journal
    DOI:https://doi.org/10.1142/s1793830922501439
    DOI ID:10.1142/s1793830922501439, ISSN:1793-8309, eISSN:1793-8317
  • Flows with time-reversal symmetric limit sets on surfaces
    Tomoo Yokoyama
    Proceedings of the American Mathematical Society, Aug. 2022, [Reviewed]

    The Long-time behavior of orbits is one of the most fundamental properties in dynamical systems. Poincaré studied the Poisson stability, which satisfies a time-reversal symmetric condition, to capture the property of whether points return arbitrarily near the initial positions after a sufficiently long time. Birkhoff introduced and studied the concept of non-wandering points, which is one of the time-reversal symmetric conditions. Moreover, minimality and pointwise periodicity satisfy the time-reversal symmetric condition for limit sets. This paper characterizes flows with the time-reversal symmetric condition for limit sets, which refine the characterization of irrational or Denjoy flows by Athanassopoulos. Using the description, we construct flows on a sphere with Lakes of Wada attractors and with an arbitrarily large number of complementary domains, which are flow versions of such examples of spherical homeomorphisms constructed by Boroński, Činč, and Liu.


    American Mathematical Society (AMS), Scientific journal
    DOI:https://doi.org/10.1090/proc/16113
    DOI ID:10.1090/proc/16113, ISSN:0002-9939, eISSN:1088-6826
  • Optimization of Flow Distribution by Topological Description and Machine Learning in Solution Growth of SiC
    Masaru Isono; Shunta Harada; Kentaro Kutsukake; Tomoo Yokoyama; Miho Tagawa; Toru Ujihara
    Advanced Theory and Simulations, Volume:5, Number:9, First page:2200302, Last page:2200302, Jul. 2022, [Reviewed]
    Wiley, Scientific journal
    DOI:https://doi.org/10.1002/adts.202200302
    DOI ID:10.1002/adts.202200302, ISSN:2513-0390, eISSN:2513-0390
  • Topological bifurcation structure of one-parameter families of C1 unimodal maps               
    Atsuro Sannami; Tomoo Yokoyama
    Nonlinearity, Volume:34, Number:11, First page:7991, Last page:8016, Oct. 2021, [Reviewed]
  • A homological approach to a mathematical definition of pulmonary fibrosis and emphysema on computed tomography               
    Naoya Tanabe; Shizuo Kaji; Susumu Sato; Tomoo Yokoyama; Tsuyoshi Oguma; Kiminobu Tanizawa; Tomohiro Handa; Takashi Sakajo; Toyohiro Hirai
    Journal of Applied Physiology, Volume:131, Number:2, First page:601, Last page:612, Aug. 2021, [Reviewed], [International magazine]
    This study proposes a homological approach to mathematically define a three-dimensional texture feature of emphysema and fibrosis on chest computed tomography using persistent homology. The proposed definition enabled accurate segmentation with comparable quality to deep learning while offering higher interpretability than deep learning-based methods.
    American Physiological Society, English, Scientific journal
    DOI:https://doi.org/10.1152/japplphysiol.00150.2021
    DOI ID:10.1152/japplphysiol.00150.2021, ISSN:8750-7587, eISSN:1522-1601, PubMed ID:34138650
  • Complete transition diagrams of generic Hamiltonian flows with a few heteroclinic orbits
    Tetsuo Yokoyama; Tomoo Yokoyama
    Discrete Mathematics, Algorithms and Applications, First page:2150023, Last page:2150023, Oct. 2020, [Reviewed]
    We study the transition graph of generic Hamiltonian surface flows, whose vertices are the topological equivalence classes of generic Hamiltonian surface flows and whose edges are the generic transitions. Using the transition graph, we can describe time evaluations of generic Hamiltonian surface flows (e.g., fluid phenomena) as walks on the graph. We propose a method for constructing the complete transition graph of all generic Hamiltonian flows. In fact, we construct two complete transition graphs of Hamiltonian surface flows having three and four genus elements. Moreover, we demonstrate that a lower bound on the transition distance between two Hamiltonian surface flows with any number of genus elements can be calculated by solving an integer programming problem using vector representations of Hamiltonian surface flows.
    World Scientific Pub Co Pte Lt, Scientific journal
    DOI:https://doi.org/10.1142/s1793830921500233
    DOI ID:10.1142/s1793830921500233, ISSN:1793-8309, eISSN:1793-8317
  • Existence and Non-existence of Length Averages for Foliations
    中野 雄史; 横山 知郎
    Communications in Mathematical Physics, Volume:372, Number:254, First page:1, Last page:17, Dec. 2019, [Reviewed]
    Springer, English, Scientific journal
    DOI:https://doi.org/10.1007/s00220-019-03490-9
    Scopus:https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85068156200&origin=inward
    Scopus Citedby:https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=85068156200&origin=inward
    DOI ID:10.1007/s00220-019-03490-9, ISSN:0010-3616, eISSN:1432-0916, SCOPUS ID:85068156200
  • パーシステントホモロジーとレーブグラフを用いた2 次元ハミルトンベクトル場の流線位相構造の自動抽出アルゴリズム               
    宇田 智紀; 横山 知郎; 坂上 貴之
    Volume:29, Number:2, First page:187, Last page:224, Jun. 2019, [Reviewed]
    Japanese, Scientific journal
    DOI:https://doi.org/10.11540/jsiamt.29.2_187
    DOI ID:10.11540/jsiamt.29.2_187, CiNii Articles ID:130007667178
  • 多重連結領域上の安定非圧縮流のプリミティブな局所構造変換               
    横山哲郎; 横山知郎
    Volume:J102-D, Number:3, First page:235, Last page:238, Mar. 2019, [Reviewed]
  • Properness of foliations               
    Tomoo Yokoyama
    Topology and its Applications, Jan. 2019, [Reviewed]
    English, Scientific journal
  • Rep-cubes: Dissection of a Cube into Nets               
    Dawei XU; Jinfeng HUANG; Yuta NAKANE; Tomoo YOKOYAMA; Takashi HORIYAMA; Ryuhei UEHARA
    IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, Volume:101-A, Number:9, First page:1420, Last page:1430, Sep. 2018, [Reviewed]
    English, Scientific journal
    DOI:https://doi.org/10.1587/transfun.E101.A.1420
    DOI ID:10.1587/transfun.E101.A.1420, DBLP ID:journals/ieicet/XuHNYHU18
  • ハミルトン曲面流に対応する流れの向きを考慮した極大語の列挙アルゴリズム               
    横山 哲郎; 横山 知郎
    Aug. 2018, [Reviewed]
    Japanese, Scientific journal
  • Tree representations of streamline topologies of structurally stable 2D incompressible flows               
    T. Sakajo; T. Yokoyama
    IMA Journal of Applied Mathematics, Volume:83, First page:380, Last page:411, Mar. 2018, [Reviewed]
    English, Scientific journal
  • Algorithms Enumerating Words of Hamiltonian Surface Flow               
    横山哲郎; 横山知郎
    Oct. 2017, [Reviewed]
    Japanese, Scientific journal
  • Genericity for non-wandering surface flows               
    T. Yokoyama
    Journal of Dynamical and Control Systems, Oct. 2015, [Reviewed]
    English, Scientific journal
  • A topological characterization for non-wandering surface flows               
    Tomoo Yokoyama
    Proceedings of the American Mathematical Society, Volume:144, Number:1, First page:315, Last page:323, Sep. 2015, [Reviewed]
    Scientific journal
    DOI:https://doi.org/10.1090/proc/12898
    DOI ID:10.1090/proc/12898, ISSN:0002-9939, eISSN:1088-6826, Web of Science ID:WOS:000364414300028
  • Transitions between streamline topologies of structurally stable Hamiltonian flows in multiply connected domains               
    Takashi Sakajo; Tomoo Yokoyama
    PHYSICA D-NONLINEAR PHENOMENA, Volume:307, First page:22, Last page:41, Jul. 2015, [Reviewed]
    English, Scientific journal
    DOI:https://doi.org/10.1016/j.physd.2015.05.013
    DOI ID:10.1016/j.physd.2015.05.013, ISSN:0167-2789, eISSN:1872-8022, Web of Science ID:WOS:000359174800003
  • Relativistic helicity and link in Minkowski space-time               
    Z. Yoshida; Y. Kawazura; T. Yokoyama
    JOURNAL OF MATHEMATICAL PHYSICS, Volume:55, Number:4, Apr. 2014, [Reviewed]
    English, Scientific journal
    DOI:https://doi.org/10.1063/1.4872236
    DOI ID:10.1063/1.4872236, ISSN:0022-2488, eISSN:1089-7658, Web of Science ID:WOS:000336084100029
  • Unique encoding for streamline topologies of incompressible and inviscid flows in multiply connected domains               
    T. Sakajo; Y. Sawamura; T. Yokoyama
    Fluid Dynamics Research, Volume:46, Number:3, First page:031411, Last page:031411, 2014, [Reviewed]
    English, Scientific journal
    DOI:https://doi.org/10.1088/0169-5983/46/3/031411
    DOI ID:10.1088/0169-5983/46/3/031411, ISSN:0169-5983, eISSN:1873-7005, SCOPUS ID:84901660669, Web of Science ID:WOS:000338839200012
  • Recurrence, pointwise almost periodicity and orbit closure relation for flows and foliations               
    Tomoo Yokoyama
    Topology and its Applications, Volume:160, Number:17, First page:2196, Last page:2206, Nov. 2013, [Reviewed]
    English, Scientific journal
    DOI:https://doi.org/10.1016/j.topol.2013.09.004
    DOI ID:10.1016/j.topol.2013.09.004, ISSN:0166-8641, eISSN:1879-3207, Web of Science ID:WOS:000326953100005
  • R-closed homeomorphisms on surfaces               
    Tomoo Yokoyama
    Topology and its Applications, Volume:160, Number:14, First page:1870, Last page:1875, Sep. 2013, [Reviewed]
    English, Scientific journal
    DOI:https://doi.org/10.1016/j.topol.2013.07.016
    DOI ID:10.1016/j.topol.2013.07.016, ISSN:0166-8641, Web of Science ID:WOS:000324973100003
  • On the relation between completeness and H-closedness of pospaces without infinite antichains               
    横山 知郎
    Algebra and Discrete Mathematics, Volume:15, Number:2, First page:287, Last page:294, May 2013, [Reviewed]
    Lugansk Taras Shevchenko Natl. Univ., English, Scientific journal
  • Word representation of streamline topologies for structurally stable vortex flows in multiply connected domains               
    Tomoo Yokoyama; Takashi Sakajo
    Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences, Volume:469, Number:2150, First page:20120558, Last page:20120558, Feb. 2013, [Reviewed]
    English, Scientific journal
    DOI:https://doi.org/10.1098/rspa.2012.0558
    DOI ID:10.1098/rspa.2012.0558, ISSN:1364-5021, eISSN:1471-2946, Web of Science ID:WOS:000312886500008
  • Minimal sets of R-closed surface homeomorphisms               
    Tomoo Yokoyama
    Comptes Rendus Mathematique, Volume:350, Number:23-24, First page:1051, Last page:1053, Dec. 2012, [Reviewed]
    English, Scientific journal
    DOI:https://doi.org/10.1016/j.crma.2012.11.002
    DOI ID:10.1016/j.crma.2012.11.002, ISSN:1631-073X, Web of Science ID:WOS:000313022900012
  • Codimension one minimal foliations whose leaves have fundamental groups with the same polynomial growth               
    Tomoo Yokoyama
    Comptes Rendus Mathematique, Volume:350, Number:5-6, First page:285, Last page:287, Mar. 2012, [Reviewed]
    Scientific journal
    DOI:https://doi.org/10.1016/j.crma.2012.03.008
    DOI ID:10.1016/j.crma.2012.03.008, ISSN:1631-073X, Web of Science ID:WOS:000304234800013
  • On some classes of spectral posets               
    横山 知郎
    Tsukuba journal of mathematics, Volume:34, Number:2, First page:213, Last page:219, Dec. 2010, [Reviewed]
    University of Tsukuba, Institute of Mathematics, English, Scientific journal
    ISSN:0387-4982, CiNii Articles ID:120006309489, CiNii Books ID:AA00874643
  • Fixed points of certain Anosov maps on Riemannian manifolds               
    TOMOO YOKOYAMA
    Ergodic Theory and Dynamical Systems, Volume:30, Number:4, First page:1261, Last page:1270, Aug. 2010, [Reviewed]
    English, Scientific journal
    DOI:https://doi.org/10.1017/s0143385709000492
    DOI ID:10.1017/s0143385709000492, ISSN:0143-3857, eISSN:1469-4417, Web of Science ID:WOS:000280510600016
  • A Poset with Spectral Scott Topology is a Quasialgebraic Domain               
    Tomoo Yokoyama
    Order, Volume:26, Number:4, First page:331, Last page:335, Dec. 2009, [Reviewed]
    English, Scientific journal
    DOI:https://doi.org/10.1007/s11083-009-9129-5
    DOI ID:10.1007/s11083-009-9129-5, ISSN:0167-8094, eISSN:1572-9273, Web of Science ID:WOS:000271751400005
  • A solution to a spectral poset problem of Lewis and Ohm               
    Tomoo Yokoyama
    Topology and its Applications, Volume:156, Number:13, First page:2220, Last page:2223, Aug. 2009, [Reviewed]
    English, Scientific journal
    DOI:https://doi.org/10.1016/j.topol.2009.05.004
    DOI ID:10.1016/j.topol.2009.05.004, ISSN:0166-8641, Web of Science ID:WOS:000268317800009
  • A counterexample for some problem for de Groot dual iterations               
    Tomoo Yokoyama
    Topology and its Applications, Volume:156, Number:13, First page:2224, Last page:2225, Aug. 2009, [Reviewed]
    English, Scientific journal
    DOI:https://doi.org/10.1016/j.topol.2009.05.005
    DOI ID:10.1016/j.topol.2009.05.005, ISSN:0166-8641, Web of Science ID:WOS:000268317800010
  • Codimension one minimal foliations and the higher homotopy groups of leaves               
    Tomoo Yokoyama
    Comptes Rendus Mathematique, Volume:347, Number:11-12, First page:655, Last page:658, Jun. 2009, [Reviewed]
    Scientific journal
    DOI:https://doi.org/10.1016/j.crma.2009.03.017
    DOI ID:10.1016/j.crma.2009.03.017, ISSN:1631-073X, Web of Science ID:WOS:000266534100016
  • Codimension one minimal foliations and the fundamental groups of leaves               
    Tomoo Yokoyama; Takashi Tsuboi
    Annales de l’institut Fourier, Volume:58, Number:2, First page:723, Last page:731, Jan. 2008, [Reviewed]
    English, Scientific journal
    DOI:https://doi.org/10.5802/aif.2366
    DOI ID:10.5802/aif.2366, ISSN:0373-0956, eISSN:1777-5310, Web of Science ID:WOS:000256687000012
■ MISC
  • 推しの数学               
    横山知郎
    First page:4, Last page:4, 11 Oct. 2023
  • Word Representation of Streamline Topologies for Flow Structure Analysis               
    Yosuke Kasai, Tomoo Yokoyama, Masahiro Kanazaki, Akira Oyama
    Nagare : journal of Japan Society of Fluid Mechanics, Volume:40, Number:2, First page:107, Last page:110, Apr. 2021
  • Visualization of Topology of Flow
    Tomoo YOKOYAMA
    Journal of the Visualization Society of Japan, Volume:41, Number:162, First page:33, Last page:34, 2021
    The Visualization Society of Japan
    DOI:https://doi.org/10.3154/jvs.41.162_33
    DOI ID:10.3154/jvs.41.162_33, ISSN:0916-4731, eISSN:1884-037X
  • トポロジーと微分方程式               
    横山知郎
    Volume:12, First page:38, Last page:44, 2020
  • Applications of Topological Flow Data Analysis to Real World Issues               
    Tomoo Yokoyama; Takashi Sakajo; Yu Sumoto
    Bulletin of the Japan Society for Industrial and Applied Mathematics, Volume:32, Number:1, First page:27, Last page:31, 2020
  • 二次元多重連結領域内における構造安定な非圧縮流れの文字列表現アルゴリズム (生物流体力学における流れ構造の解析と役割)               
    坂上 貴之; 横山 知郎; 澤村 陽一
    Volume:1900, First page:11, Last page:25, Jun. 2014
    Japanese
    ISSN:1880-2818, CiNii Articles ID:110009814710, CiNii Books ID:AN00061013
  • 28aAJ-7 Helicity of Relativistic Fluid/Plasma : Link in Minkowski Space-Time               
    Yoshida Z.; Kawazura Y.; Yokoyama T.
    Meeting abstracts of the Physical Society of Japan, Volume:69, Number:1, First page:316, Last page:316, 05 Mar. 2014
    The Physical Society of Japan (JPS), Japanese
    ISSN:1342-8349, CiNii Articles ID:110009834685, CiNii Books ID:AA11439205
■ Lectures, oral presentations, etc.
  • Topological bifurcation structure of one-parameter families of C^1 unimodal maps               
    横山知郎
    Mar. 2025
  • A Poincaré-Bendixson theorem for flows with arbitrarily many singular points               
    Tomoo Yokoyama
    ANZIAM 2025, Feb. 2025, [International conference]
    Oral presentation
  • Limit behaviors of flows on surfaces               
    横山知郎
    Oct. 2024
  • Dependency of the positive and negative long-time behaviors of flows on surfaces               
    横山知郎
    Sep. 2024
  • A Poincaré-Bendixson theorem for flows with arbitrarily many singular points               
    Tomoo Yokoyama
    Saitama Dynamics 2024, Sep. 2024, [International conference]
  • Classification of streamline topology of vortex flows in doubly periodic domains               
    Tomoo Yokoyama
    ICTAM 2024, Aug. 2024, [International conference]
    Oral presentation
  • Structural stability of “incompressible” line fields on surfaces and generic intermediate line fields               
    横山知郎
    Jun. 2024
  • Topological study of 2D flows and its application               
    Tomoo Yokoyama
    The Grad Conjecture in Fluid Mechanics and Magnetohydrodynamics: Theory and Applications, Mar. 2024, [International conference]
  • Topological Data Analysis for line fields and its relative topics               
    Tomoo Yokoyama
    Feb. 2024, [Domestic conference]
    Oral presentation
  • On blowups of stagnation points of 2D potential flows               
    Applied Complex and Computational Analysis Meeting, Feb. 2024, [International conference]
  • On semi-decomposition               
    Tomoo Yokoyama
    Nov. 2023, [Domestic conference]
  • 曲面上の流れの正方向と負方向の極限の振る舞いの依存性               
    Tomoo Yokoyama
    Nov. 2023, [Domestic conference]
  • Topological Flow Data Analysis and its relative topics               
    Tomoo Yokoyama
    Oct. 2023, [Domestic conference]
  • Irregular behavior in foliations (Mini-course)               
    Dynamics of Foliations, University of Porto, Sep. 2023, [International conference]
  • Existence and Non-existence of Length Averages for Foliations               
    Tomoo Yokoyama
    Geometry and Probability 2023, Aug. 2023, [International conference]
  • Generic transitions for flows on surfaces with or without constraints               
    Tomoo Yokoyama
    ICIAM 2023 Tokyo Minisymposium Topological data analysis and machine learning, Aug. 2023, [International conference]
  • Dependency of the positive and negative long-time behaviors of flows on surfaces               
    Tomoo Yokoyama
    Jun. 2023, [Domestic conference]
  • 曲面上の流れの極限集合について               
    Tomoo Yokoyama
    May 2023, [Domestic conference]
  • トポロジカルな流れの解析とその応用について               
    2021
    Invited oral presentation
■ Research projects
  • Singularity analysis of complex functions for describing complex phenomena               
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (A), 01 Apr. 2023 - 31 Mar. 2028
    Kyoto University
    Grant amount(Total):44200000, Direct funding:34000000, Indirect funding:10200000
    Grant number:23H00086
  • Deepening of a unified framework for treating topological dynamical systems, decomposition theory, and topological data analysis               
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (C), Apr. 2024 - Mar. 2028
    Saitama University
    Grant amount(Total):3770000, Direct funding:2900000, Indirect funding:870000
    Grant number:24K06733
  • New studies of foliations and dynamical systems, and their applications               
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), 01 Apr. 2021 - 31 Mar. 2026
    The University of Tokyo
    Grant amount(Total):12480000, Direct funding:9600000, Indirect funding:2880000
    Grant number:23K20793
  • New studies of foliations and dynamical systems, and their applications               
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), 01 Apr. 2021 - 31 Mar. 2026
    The University of Tokyo
    Grant amount(Total):12480000, Direct funding:9600000, Indirect funding:2880000
    Grant number:21H00980
  • Complementary study on dynamical systems and foliations using methods of partially ordered set and general topology               
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (C), 01 Apr. 2020 - 31 Mar. 2024
    Grant amount(Total):4030000, Direct funding:3100000, Indirect funding:930000
    Grant number:20K03583
  • Vortex dynamics on surfaces exploring new fluid phenomena brought by geometry               
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), 01 Apr. 2018 - 31 Mar. 2022
    Kyoto University
    Grant amount(Total):16640000, Direct funding:12800000, Indirect funding:3840000
    Grant number:18H01136
  • 流れの位相的な文字化理論とその計算機上への実装               
    2016 - 2019
■ Industrial Property Rights
  • 有限型の流れパターンの語表現装置、語表現方法、プログラム、構造物形状の学習方法および構造物設計方法               
    Patent right
  • 流れパターンの正規表現作成方法、正規表現作成装置、および、コンピュータが実行可能なプログラム               
    Patent right
  • 流体遷移分析装置、流体遷移分析方法、および、プログラム               
    Patent right
  • 流れパターンの語表現方法、語表現装置、および、プログラム               
    Patent right
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