Updated on 2026/07/01

写真a

 
NOSAKA TAKEFUMI
 
Organization
School of Science Associate Professor
Title
Associate Professor
Profile
数学者であり、特に位相幾何学(トポロジー)を専門にしている。そのうち3次元多様体のコホモロジーや基本群を中心に研究している。
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Research Interests

  • Geometry, topology, quandle

Research Areas

  • Natural Science / Geometry  / low-dimensional topology

Education

  • Kyoto University

    2009.4 - 2012.3

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  • Kyoto University

    2007.4 - 2009.3

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  • Kyoto University   Faculty of Science

    2003.4 - 2007.3

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Research History

  • Institute of Science Tokyo   Associate Professor

    2024.10

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    Country:Japan

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  • Tokyo Institute of Technology   Department of Mathematics   Associate Professor

    2017.4 - 2024.9

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  • Kyushu University   Faculty of Mathematics   assosiated proffesor

    2012.10 - 2017.3

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Papers

  • Meta-nilpotent knot invariants and symplectic automorphism groups of free nilpotent groups Reviewed

    Takefumi Nosaka

    Journal of Knot Theory and Its Ramifications   2026.5

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    Publishing type:Research paper (scientific journal)   Publisher:World Scientific Pub Co Pte Ltd  

    In this paper, we study nilpotent [Formula: see text]-localizations of knot groups using the symplectic automorphism groups of free nilpotent groups. We show that any function on the set of conjugacy classes in the corresponding outer automorphism group defines a knot invariant. Furthermore, we study these automorphism groups and compute several invariants arising from this construction.

    DOI: 10.1142/s021821652650032x

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  • Symmetric skew-racks and cocycle invariants of closed 3-manifolds Reviewed

    Takefumi Nosaka

    Algebraic & Geometric Topology   26 ( 4 )   1451 - 1464   2026.4

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    Authorship:Lead author   Language:English  

    DOI: 10.48550/arXiv.2303.12995

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  • The Dijkgraaf-Witten invariants from second Chern classes Reviewed

    Takefumi Nosaka

    Math. J. Okayama Univ.   68   63 - 75   2026.1

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    Language:English   Publishing type:Research paper (scientific journal)  

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  • Non-acyclic Reidemeister torsions of manifolds of odd dimension Reviewed

    Takefumi Nosaka, Naoko Wakijo, Koki Yanagida

    Commun. Korean Math. Soc.   40 ( 2 )   421 - 446   2025.4

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    Language:English  

    DOI: 10.4134/CKMS.c240148

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  • Fox pairings of Poincaré duality groups Reviewed

    Takefumi NOSAKA

    Hokkaido Mathematical Journal   53 ( 2 )   2024.6

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    Authorship:Lead author   Publishing type:Research paper (scientific journal)   Publisher:Department of Mathematics, Hokkaido University  

    DOI: 10.14492/hokmj/2022-646

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  • A solvable extended logarithm of the Johnson homomorphism Reviewed

    Takefumi Nosaka

    Journal of Topology and Analysis   17 ( 06 )   1773 - 1786   2024.2

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    Authorship:Lead author   Language:English   Publishing type:Research paper (scientific journal)   Publisher:World Scientific Pub Co Pte Ltd  

    Concerning Johnson’s homomorphism from the Torelli group, there are previous works to define a logarithm of the homomorphism, and give some extension of the logarithm. This paper considers exponential solvable elements in the mapping class group of a surface, and defines the logarithms of such elements.

    DOI: 10.1142/s1793525324500079

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  • Reciprocity of the Chern–Simons invariants of 3-manifolds Reviewed

    Takefumi Nosaka

    Letters in Mathematical Physics   114 ( 1 )   2024.1

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    Authorship:Lead author   Publishing type:Research paper (scientific journal)   Publisher:Springer Science and Business Media LLC  

    DOI: 10.1007/s11005-023-01760-1

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    Other Link: https://link.springer.com/article/10.1007/s11005-023-01760-1/fulltext.html

  • Twisted Alexander Invariants of Knot Group Representations Reviewed

    Takefumi Nosaka

    Tokyo Journal of Mathematics   45 ( 1 )   2022.6

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    Authorship:Lead author   Publishing type:Research paper (scientific journal)   Publisher:Tokyo Journal of Mathematics  

    DOI: 10.3836/tjm/1502179346

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  • Twisted cohomology pairings of knots II; to some Blanchfield pairings

    T. Nosaka

    Journal of Knot Theory and Its Ramifications   31 ( 07 )   2022.6

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:World Scientific Pub Co Pte Ltd  

    In this paper, we study some comparison between a bilinear cohomology pairing in local coefficients and the Blanchfield pairing of a knot. We show that the former pairing is an [Formula: see text]-equivalent invariant, and give a criterion to a relation between the two pairings. We also observe that the pairings of some knots are equivalent, and that the pairings of other knots are not equivalent.

    DOI: 10.1142/s0218216522500407

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  • Cellular chain complexes of universal covers of some 3-manifolds Reviewed

    Takefumi Nosaka

    J. Math. Sci. Univ. Tokyo   29 ( 1 )   89 - 113   2022

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    Authorship:Lead author   Language:English   Publishing type:Research paper (scientific journal)  

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  • Meta-nilpotent quotients of mapping-torus groups and two topological invariants of quadratic forms Reviewed

    Takefumi Nosaka

    Osaka J. Math   58 ( 2 )   351 - 365   2021.4

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    Authorship:Lead author   Language:English   Publishing type:Research paper (scientific journal)  

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  • Twisted Alexander invariants of knot group representations II; computation and duality Reviewed

    Takefumi Nosaka

    Topology and its Applications   107533 - 107533   2020.12

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    Authorship:Corresponding author   Publishing type:Research paper (scientific journal)   Publisher:Elsevier BV  

    DOI: 10.1016/j.topol.2020.107533

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  • Twisted cohomology pairings of knots III; triple cup products Reviewed

    Takefumi Nosaka

    Hiroshima Mathematical Journal   50 ( 2 )   2020.7

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    Authorship:Lead author, Corresponding author   Publishing type:Research paper (scientific journal)   Publisher:Hiroshima University - Department of Mathematics  

    DOI: 10.32917/hmj/1595901628

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  • Schur multipliers and second quandle homology Reviewed

    Rhea Palak Bakshi, Dionne Ibarra, Sujoy Mukherjee, Takefumi Nosaka, Józef H. Przytycki

    Journal of Algebra   552   52 - 67   2020.6

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    Publishing type:Research paper (scientific journal)   Publisher:Elsevier BV  

    DOI: 10.1016/j.jalgebra.2019.12.027

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  • Milnor invariants via unipotent Magnus embeddings Reviewed

    Hisatoshi Kodani, Takefumi Nosaka

    Topology and its Applications   271   106991 - 106991   2020.2

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    Publishing type:Research paper (scientific journal)   Publisher:Elsevier BV  

    DOI: 10.1016/j.topol.2019.106991

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  • Milnor–Orr Invariants from the Kontsevich Invariant Reviewed

    Takefumi Nosaka

    Publications of the Research Institute for Mathematical Sciences   56 ( 1 )   173 - 193   2020.1

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    Authorship:Lead author   Publishing type:Research paper (scientific journal)   Publisher:European Mathematical Society Publishing House  

    DOI: 10.4171/prims/56-1-7

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  • On the fundamental relative 3-classes of knot group representations Reviewed

    Takefumi Nosaka

    Geometriae Dedicata   1 - 24   2019.4

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    Language:English   Publishing type:Research paper (scientific journal)  

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  • Cocycles of nilpotent quotients of free groups Reviewed

    Takefumi Nosaka

    Journal of the Mathematical Society of Japan   2019

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    Language:English   Publishing type:Research paper (scientific journal)  

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  • de Rham theory and cocycles of cubical sets from smooth quandles Reviewed

    Takefumi Nosaka

    Kodai Mathematical Journal   42 ( 1 )   111 - 129   2019

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    Language:English   Publishing type:Research paper (scientific journal)  

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  • Finite presentations of centrally extended mapping class groups Reviewed

    Takefumi Nosaka

    73 ( 1 )   103 - 113   2019

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    Language:English   Publishing type:Research paper (scientific journal)  

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  • Central extensions of groups and adjoint groups of quandles Reviewed

    Takefumi Nosaka

    RIMS Kokyuroku Bessatsu   B66   167 - 184   2017.6

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    Language:English   Publishing type:Research paper (scientific journal)  

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  • Twisted cohomology pairings of knots I; diagrammatic computation Reviewed

    Takefumi Nosaka

    Geometriae Dedicata   189 ( 1 )   139 - 160   2017.2

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    Language:English   Publishing type:Research paper (scientific journal)  

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  • Bilinear-form invariants of Lefschetz-fibrations over the 2-sphere Reviewed

    Takefumi Nosaka

    Journal of Gokova Geometry Topology   11   32 - 55   2017

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    Language:English   Publishing type:Research paper (scientific journal)  

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  • Longitudes in SL_2 representations of knot groups and Milnor-Witt K_2 groups of fields Reviewed

    Takefumi Nosaka

    Annals of K-Theory   2   211 - 233   2016.12

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  • Homotopical interpretation of link invariants from finite quandles Reviewed

    Takefumi Nosaka

    TOPOLOGY AND ITS APPLICATIONS   193   1 - 30   2015.9

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1016/j.topol.2015.05.087

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  • On third homologies of groups and of quandles via the Dijkgraaf-Witten invariant and Inoue-Kabaya map Reviewed

    Takefumi Nosaka

    ALGEBRAIC AND GEOMETRIC TOPOLOGY   14 ( 5 )   2655 - 2691   2014

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.2140/agt.2014.14.2655

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  • Quandle cocycles from invariant theory Reviewed

    Takefumi Nosaka

    ADVANCES IN MATHEMATICS   245   423 - 438   2013.10

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1016/j.aim.2013.05.022

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  • On quandle homology groups of Alexander quandles of prime order Reviewed

    Takefumi Nosaka

    Transactions of the American Mathematical Society   365   3413 - 3436   2013.1

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    Language:English   Publishing type:Research paper (scientific journal)  

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  • Quandle homotopy invariants of knotted surfaces Reviewed

    Takefumi Nosaka

    Mathematische Zeitschrift   274   341 - 365   2012.10

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    Language:English   Publishing type:Research paper (scientific journal)  

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  • SOME TOPOLOGICAL ASPECTS OF 4-FOLD SYMMETRIC QUANDLE INVARIANTS OF 3-MANIFOLDS Reviewed

    Eri Hatakenaka, Takefumi Nosaka

    INTERNATIONAL JOURNAL OF MATHEMATICS   23 ( 7 )   2012.7

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1142/S0129167X12500644

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  • On homotopy groups of quandle spaces and the quandle homotopy invariant of links Reviewed

    Takefumi Nosaka

    TOPOLOGY AND ITS APPLICATIONS   158 ( 8 )   996 - 1011   2011.5

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1016/j.topol.2011.02.006

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  • 4-fold symmetric quandle invariants of 3-manifolds Reviewed

    Takefumi Nosaka

    ALGEBRAIC AND GEOMETRIC TOPOLOGY   11 ( 3 )   1601 - 1648   2011

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.2140/agt.2011.11.1601

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Books

  • Quandles and topological pairs : symmetry, knots, and cohomology

    Nosaka, Takefumi( Role: Sole author)

    Springer,[Amazon]  2017  ( ISBN:9789811067921

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    Total pages:ix, 136 p.   Language:English  

    CiNii Books

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MISC

  • 特集= あの頃に出会った定理「多様体上の1の分割の存在定理/大域と局所の結節点」

    野坂 武史

    数学セミナー   2023.9

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    Language:Japanese   Publishing type:Article, review, commentary, editorial, etc. (other)  

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  • 群による結び目の研究

    野坂 武史

    数理科学   2020.3

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    Language:Japanese   Publishing type:Article, review, commentary, editorial, etc. (other)  

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Research Projects

  • Various studies of Chern-Simons theory from 3-dimensional geometric cohomology

    Grant number:24K06708  2024.4 - 2027.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (C)

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    Grant amount:\3510000 ( Direct Cost: \2700000 、 Indirect Cost:\810000 )

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  • Nilpotent study of 3-dimensional topology

    Grant number:20K03605  2020.4 - 2023.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (C)

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    Grant amount:\3120000 ( Direct Cost: \2400000 、 Indirect Cost:\720000 )

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  • Algebraic topology of quandles, and its application to low dimensional topology

    Grant number:17K05257  2017.4 - 2020.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (C)

    Nosaka Takefumi

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    Grant amount:\4420000 ( Direct Cost: \3400000 、 Indirect Cost:\1020000 )

    The purpose of this study is to analyze quandle, which is an algebraic system, and to give its applications to the field of topology. In this study, I investigate quandles from the viewpoints of manifolds and nilpotent methods, and obtained some results. Meanwhile, given a quandle, a (co)-homology theory is defined; from the viwpoints, I calculate quandle cohomology with smoothness and the second cohomology.
    In applications to topology, I gave a procedure of computing the fundamental 3-class of a 3-dimensional manifold. If the manifold is a knot complement or we are give a nilpotent setting, I showed that the procedure can be described as a concrete formula. I also gave some results on centrality of meta-nilpotent quotient groups of the free group.

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  • Characteristic classes of quandles, and its applications to low dimensional topology

    Grant number:25800049  2013.4 - 2017.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Young Scientists (B)

    Takefumi Nosaka

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    Grant amount:\4290000 ( Direct Cost: \3300000 、 Indirect Cost:\990000 )

    The subject of this research is "a quandle", which is an algebraic system. The purpose is to explore quandle theory from broad viewpoints and by many means.
    I gave some applications to low dimensional topology, including 3-manifold, (surface) knots, branched covering space, Lefschetz fibrations, and surface braids. The study of quandle contains many mysterious areas; however, I showed that homotopy theory, group cohomology, bordism groups, invariant theory, algebraic K-theory are useful to quandle theory. Furthermore, as an unexpected development, I also pointed out that quandle theory is compatible with secondary characteristics, bilinear forms, and cup products.

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Teaching Experience

  • ベクトル解析

    2024.10 - 2025.3

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  • Linear algebra

    2018.4 Institution:Tokyo Institute of Technology

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