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SATOH ShinGraduate School of Science / Division of MathematicsProfessor
Research activity information
■ Paper- Hiroshima University - Department of Mathematics, Jul. 2025, Hiroshima Mathematical Journal, 55(2) (2)Scientific journal
- In the previous papers, we introduced three intersection polynomials of a virtual knot. In this paper, we prove that the first and second intersection polynomials are finite-type invariants of order two with respect to crossing change. We also study virtual knots of supporting genus one, and give a relation between the first and second intersection polynomials of such a virtual knot.World Scientific Pub Co Pte Ltd, Feb. 2025, Journal of Knot Theory and Its Ramifications, 34(04) (04)Scientific journal
- We introduce a local deformation called the virtualized [Formula: see text]-move for virtual knots and links. We prove that the virtualized [Formula: see text]-move is an unknotting operation for virtual knots. Furthermore we give a necessary and sufficient condition for two virtual links to be related by a finite sequence of virtualized [Formula: see text]-moves.World Scientific Pub Co Pte Ltd, Oct. 2024, Journal of Topology and Analysis, 18(02) (02), 409 - 421Scientific journal
- Oct. 2024, arXiv preprint, English
- Institute of Mathematics, Polish Academy of Sciences, 2023, Fundamenta Mathematicae, 263(3) (3), 203 - 234Scientific journal
- 2020, European J. Combin., 84, 103033 - 24 pp, EnglishWrithe polynomials and shell moves for virtual knots and links[Refereed]Scientific journal
- 2020, J. Knot Theory Ramifications, 29(8) (8), 1971002 - 11 pp, EnglishA note on coverings of virtual knots[Refereed]Scientific journal
- Sep. 2018, Topology Appl., 247, 9 - 19, EnglishThe pass move is an unknotting operation for welded knots[Refereed]Scientific journal
- 2018, J. Knot Theory Ramifications, 27(no. 8) (no. 8), 1850049 - 16 pp, EnglishFiniteness of the set of virtual knots with a given state number[Refereed]Scientific journal
- 2018, Rocky Mountain J. Math., 48(3) (3), 967 - 979, EnglishCrossing changes, delta moves and sharp moves on welded knots[Refereed]Scientific journal
- Sep. 2017, J. Knot Theory Ramifications, 26(10) (10), 1750060 - 9 pp, English[Refereed]Scientific journal
- Jul. 2017, J. Knot Theory Ramifications, 26(8) (8), 1750047 - 6 pp, English[Refereed]Scientific journal
- Apr. 2017, Topology Appl., 222, 200 - 216, EnglishThe 6- and 8-palette numbers of links[Refereed]Scientific journal
- Nov. 2016, J. Knot Theory Ramifications, 25(13) (13), 1671001 - 4 pp, English[Refereed]Scientific journal
- Apr. 2016, J. Knot Theory Ramifications, 25(4) (4), 1650017 - 22 pp, English[Refereed]Scientific journal
- 2016, Algebr. Geom. Topol., 16(6) (6), 3325 - 3359, English[Refereed]Scientific journal
- Dec. 2015, Topology Appl., 196(B) (B), 846 - 851, English[Refereed]Scientific journal
- Dec. 2015, Topology Appl., 196(B) (B), 754 - 770, English[Refereed]Scientific journal
- Dec. 2015, Topology Appl., 196(B) (B), 771 - 776, English[Refereed]Scientific journal
- Oct. 2014, J. Knot Theory Ramifications, 23(12) (12), 1450059 - 15 pp, English[Refereed]Scientific journal
- Mar. 2014, J. Knot Theory Ramifications, 23(3) (3), 1450016 - 27 pp, English[Refereed]Scientific journal
- Mar. 2014, Hiroshima Math. J., 44(1) (1), 63 - 74, English7-colored 2-knot diagram with six colors[Refereed]Scientific journal
- 2014, Fund. Math., 225(1) (1), 327 - 342, English[Refereed]Scientific journal
- Yokohama City Unicersity and Yokohama National University, 2013, Yokohama Math. J., 59, 91 - 97, EnglishThe pallet graph of a Fox coloring[Refereed]Scientific journal
- Oct. 2012, J. Knot Theory Ramifications, 21(12) (12), 1250117 - 11 pp, English[Refereed]Scientific journal
- Sep. 2012, J. Knot Theory Ramifications, 21(10) (10), 1250095 - 18 pp, English[Refereed]Scientific journal
- Jan. 2012, Proc. Amer. Math. Soc., 140(1) (1), 367 - 376, EnglishOn the crossing numbers of a virtual knot[Refereed]Scientific journal
- Mar. 2010, Hiroshima Math. J., 40(1) (1), 1 - 15, EnglishA note on the sheet numbers of twist-spun knots[Refereed]Scientific journal
- Dec. 2009, Osaka J. Math., 46(4) (4), 939 - 948, English5-colored knot diagram with four colors[Refereed]Scientific journal
- Sep. 2009, Kyushu J. Math., 63(2) (2), 239 - 252, English[Refereed]Scientific journal
- Apr. 2009, J. Math. Soc. Japan, 61(2) (2), 579 - 606, English[Refereed]Scientific journal
- Sep. 2007, J. Knot Theory Ramifications, 16(7) (7), 959 - 967, EnglishA note on the shadow cocycle invariant of a knot with a base point[Refereed]Scientific journal
- 2007, Intelligence of low dimensional topology 2006, Ser. Knots Everything, 40, 287 - 291, EnglishSheet numbers and cocycle invariants of surface-knots[Refereed][Invited]International conference proceedings
- Sep. 2006, Topology Appl., 153(15) (15), 2788 - 2794, English[Refereed]Scientific journal
- Feb. 2006, J. Aust. Math. Soc., 80(1) (1), 131 - 147, EnglishRibbon concordance of surface-knots via quandle cocycle invariants[Refereed]Scientific journal
- 2006, Proc. Amer. Math. Soc., 134(9) (9), 2779 - 2783, EnglishRibbon-moves for 2-knots with 1-handles attached and Khovanov-Jacobsson numbers[Refereed]Scientific journal
- 2006, Trans. Amer. Math. Soc., 358(12) (12), 5425 - 5439, EnglishThe Braid index is not additive for the connected sum of 2-knots[Refereed]Scientific journal
- Nov. 2005, J. Knot Theory Ramifications, 14(7) (7), 853 - 858, English[Refereed]Scientific journal
- 2005, Proc. Amer. Math. Soc., 133(2) (2), 613 - 616, EnglishNon-additivity for triple point numbers on the connected sum of surface-knots[Refereed]Scientific journal
- 2005, Bull. London Math. Soc., 37(2) (2), 285 - 296, EnglishAn infinite family of non-invertible surfaces in 4-space[Refereed]Scientific journal
- 2005, New Zealand J. Math., 34(1) (1), 71 - 79, EnglishTriple point numbers and quandle cocycle invariants of knotted surfaces in 4-space[Refereed]Scientific journal
- 2005, Houston J. Math, 31(3) (3), 721 - 741, EnglishLiftability for double coverings of immersions of non-orientable surfaces into 3-space[Refereed]Scientific journal
- 2005, Osaka J. Math., 42(3) (3), 543 - 556, EnglishNo 2-knot has triple point number two or three[Refereed]Scientific journal
- 2004, Trans. Amer. Math. Soc., 356(3) (3), 1007 - 1024, EnglishThe 2-twist-spun trefoil has the triple point number four[Refereed]Scientific journal
- 2004, J. Knot Theory Ramifications, 13(7) (7), 845 - 856, EnglishA note on non-classical virtual knots[Refereed]Scientific journal
- Kobe University, 2004, Kobe J. Math., 21(1-2) (1-2), 71 - 82, EnglishA note on unknotting numbers of twist-spun knots[Refereed]Scientific journal
- 2003, Proceedings of the Winter Workshop of Topology/Workshop of Topology and Computer, Interdiscip. Inform. Sci., 9(1) (1), 127 - 140, EnglishTangles with up to seven crossings[Refereed][Invited]International conference proceedings
- 2002, Proceedings of the First Joint Japan-Mexico Meeting in Topology (Morelia, 1999), Topology Appl., 121(1-2) (1-2), 207 - 218, EnglishTriple point invariants of non-orientable surface-links[Refereed]International conference proceedings
- 2002, Knots 2000 Korea, Vol. 1 (Yongpyong), J. Knot Theory Ramifications, 11(3) (3), 413 - 430, EnglishSurface diagrams of twist-spun 2-knots[Refereed]International conference proceedings
- 2002, Michigan Math. J., 50(3) (3), 575 - 591, EnglishBordism of undirected surfaces in 4-space[Refereed]Scientific journal
- 2002, Illinois J. Math., 46(2) (2), 467 - 475, EnglishA virtualized skein relation for Jones polynomials[Refereed]Scientific journal
- Hiroshima University, 2002, Hiroshima Math. J., 32(3) (3), 351 - 369, EnglishCongruence formulae for stable maps of surfaces[Refereed]Scientific journal
- Kobe University, 2002, Kobe J. Math., 19(1-2) (1-2), 51 - 59, EnglishPositive, alternating, and pseudo-ribbon surface-knots[Refereed]Scientific journal
- 2001, Pacific J. Math., 197(1) (1), 213 - 221, EnglishMinimal triple point numbers of some non-orientable surface-links[Refereed]Scientific journal
- 2001, Algebr. Geom Topol., 1, 299 - 310, EnglishA theorem of Sanderson on link bordisms in dimension 4[Refereed]Scientific journal
- 2001, Illinois J. Math., 45(3) (3), 823 - 832, EnglishDouble decker sets of generic surfaces in 3-space as homology classes[Refereed]Scientific journal
- 2000, Proc. Amer. Math. Soc., 128(9) (9), 2789 - 2793, EnglishOn non-orientable surfaces in 4-space which are projected with at most one triple point[Refereed]Scientific journal
- Osaka University and Osaka City University, Departments of Mathematics, 2000, Osaka J. Math., 37(1) (1), 73 - 92, EnglishSimplex moves on elementary surfaces[Refereed]Scientific journal
- 2000, J. Knot Theory Ramifications, 9(4) (4), 531 - 542, EnglishVirtual knot presentation of ribbon torus-knots[Refereed]Scientific journal
- 2000, Topology Appl., 106(1) (1), 103 - 113, EnglishLifting a generic surface in 3-space to an embedded surface in 4-space[Refereed]Scientific journal
- 1998, J. Knot Theory Ramifications, 7(2) (2), 217 - 230, EnglishSphere-slice links with at most five components[Refereed]Scientific journal
- Friday Seminar on Knot Theory, Nov. 2018, English, 大阪市立大学, International conferenceNo 2-knot has regular triple point number four[Invited]Invited oral presentation
- Four dimensional Topology, Sep. 2018, English, 大阪市立大学, International conferenceThe n-cable of a ribbon 2-knot[Invited]Invited oral presentation
- 拡大KOOK セミナー2018, Sep. 2018, Japanese, 大阪市立大学, Domestic conferenceDouble point circles of regular 2-knot diagrams[Invited]Invited oral presentation
- 2017 年度琉球結び目セミナー, Jan. 2018, Japanese, 那覇市ぶんかテンブス館, Domestic conference2 次元結び目の多重化について[Invited]Invited oral presentation
- 2017 年度秋季総合分科会, Sep. 2017, Japanese, 山形大学, Domestic conferenceリボン曲面タングルと曲面絡み目のダブルOral presentation
- 日本数学会・トポロジー分科会, Sep. 2017, Japanese, 山形大学理学部, Domestic conferenceA set of local moves generating the writhe polynomialOral presentation
- 拡大KOOKセミナー2017, Aug. 2017, Japanese, 大阪市立大学, Domestic conferenceA set of local moves generating the writhe polynomial[Invited]Invited oral presentation
- 2016年度琉球結び目セミナー, Dec. 2016, Japanese, 那覇市伝統工芸館, Domestic conference単純 2 次元結び目図式の OU グラフについて[Invited]Invited oral presentation
- Friday Seminar on Knot Theory, Dec. 2016, English, Osaka City Uvinersity, Domestic conferenceThe ribbon stable class of a surface-link[Invited]Invited oral presentation
- 4次元トポロジー, Nov. 2016, Japanese, Osaka City Uvinersity, Domestic conferenceFundamental deformations on unwrithed surface-kntos[Invited]Invited oral presentation
- KOOK-TAPU Workshop of Knots in Tsushima Island, Sep. 2016, English, 対馬市交流センター, International conferenceA construction of stable classes of ribon surface-knots from non-ribbon surface-knots[Invited]Invited oral presentation
- 拡大 KOOK セミナー, Aug. 2016, Japanese, Osaka Electro-Communication University, Domestic conference曲面結び目のねじれのない射影図[Invited]Invited oral presentation
- 拡大KOOKセミナー, Aug. 2016, Japanese, 神戸大学百年記念館, Domestic conferenceWeaving a fabric in 4-space[Invited]Invited oral presentation
- 2016琉球結び目セミナー, Feb. 2016, Japanese, 那覇市ぶんかテンブス館, Domestic conference曲面結び目の射影図の正則変形[Invited]Invited oral presentation
- The 11th East Asian School of Knots and Related Topics, Jan. 2016, English, 大阪市立大学, International conferenceDehn colored knot diagrams[Invited]Invited oral presentation
- Friday Seminar on Knot Theory, Oct. 2015, Japanese, 大阪市立大学, Domestic conferenceNoded knots and ribbon Kb-knots[Invited]Invited oral presentation
- トポロジーとコンピュータ2014, Nov. 2014, English, 東京大学, Domestic conferenceDescription of a surface-knot[Invited]Invited oral presentation
- 東北結び目セミナー2014, Oct. 2014, Japanese, カレッジプラザ秋田, Domestic conferenceLocal moves on welded knots[Invited]Invited oral presentation
- 日本数学会秋季総合分科会, Sep. 2014, Japanese, 広島大学, Domestic conference交差交換で溶接結び目をほどく[Invited]Invited oral presentation
- 日本数学会・トポロジー分科会, Sep. 2014, Japanese, 広島大学, Domestic conferenceDelta-crossing number for knotsOral presentation
- A Satellite Conference of Seoul ICM 2014 No. 25: Knots and Low Dimensional Manifolds, Aug. 2014, English, BEXCO, Busan, Korea, International conferenceCrossing changes unknot a welded knot[Invited]Invited oral presentation
- 写像の特異点論及び関連する科学の諸問題, Jun. 2014, Japanese, 都城工業高等専門学校, Domestic conference結び目のステイト数[Invited]Invited oral presentation
- 2014琉球結び目セミナー, Jun. 2014, Japanese, 那覇ぶんかテンブス館, Domestic conference2次元結び目のザイフェルト超曲面[Invited]Invited oral presentation
- Knots in Washington XXXVII, Jan. 2014, English, George WashingtonUniversity, Washington(米国), International conferenceEffective 9-colorings for knots[Invited]Invited oral presentation
- 2013琉球結び目セミナー, Sep. 2013, Japanese, 那覇ぶんかテンブス館, Domestic conference本質的フォックス彩色について[Invited]Invited oral presentation
- International Conferenceon Topology and Geometry 2013 - JAMEX VI, Sep. 2013, English, 島根大学, 島根, International conferenceSurface-tangle decomposition of ribbon 2-knots and twist-spun knots[Invited]Invited oral presentation
- International Conference on Topology and Geometry 2013, Joint with the 6th Japan-Mexico Topology Symposium, Sep. 2013, English, 島根大学, 島根, International conferenceDelta-crossing number for knots[Invited]Invited oral presentation
- Friday Seminar on Knot Theory, Jun. 2013, English, 大阪市立大学, 大阪市立大学, Domestic conferenceOn knots with no 3-state[Invited]Invited oral presentation
- 日本数学会2013年度年会, Mar. 2013, Japanese, 京都大学, Domestic conference結び目のOU列とその応用Oral presentation
- Knots in Washington XXXV, Dec. 2012, English, George Washington University, International conferenceThe pallet graph of a Fox coloringOral presentation
- 東北結び目セミナー2012, Oct. 2012, Japanese, 山形大学小白川キャンパス, Domestic conferenceThe pallet graph of a Fox coloringOral presentation
- 日本数学会2012年度秋季総合分科会, Sep. 2012, Japanese, 九州大学, Domestic conference平面曲線と結び目のステイト数Oral presentation
- 2012琉球結び目セミナー, Sep. 2012, Japanese, 那覇市ぶんかテンブス館, Domestic conferenceある行列式の計算とその応用Oral presentation
- 2012 TAPU Workshop on Knot Theory and Related Topics2012 TAPU Summer School on Quandle Theory(The 4th TAPU-KOOK Joint Seminar on Knot Theory and Related Topicsand The 6th Graduate Student Workshop on Mathematics), Jul. 2012, English, Pusan National University, International conferenceCrossing information and warping polynomials about the trefoil knot[Invited]Invited oral presentation
- The 8th East Asian School of Knots and Related Topics, Jan. 2012, English, 河内 明夫, KAIST, Daejeon, Korea, International conferenceVirtual graph presentations of ribbon surface-knots[Invited]Invited oral presentation
- Quantum Topology/Hopf Algebra Seminar, Oct. 2011, English, L. H. Kauffman, Illinois University at Chicago, International conferenceNon-identical twin groups of virtual knot[Invited]Invited oral presentation
- Virtual Seminar, Sep. 2011, English, D. Roseman, Iowa University, International conferenceQuandle cocycle invariants of roll-spun knots[Invited]Invited oral presentation
- Intelligence of Low-dimensional Topology, May 2011, Japanese, 大槻 知忠, 京都大学数理解析研究所, Domestic conferenceQuandle cocycle invariants of roll-spun knots[Invited]Invited oral presentation
- 日本数学会年会, Mar. 2011, Japanese, 日本数学会, 早稲田大学, Domestic conferenceロールスパン結び目のカンドル不変量Oral presentation
- Mathematics Colloquium, Sep. 2010, English, M. Saito, University of South Florida, U.S.A., International conferenceFox colorings and cocycle invariants of roll-spun knots[Invited]Invited oral presentation
- Knots in Chicago, Sep. 2010, English, L. H. Kauffman, University of Illinois at Chicago, U.S.A., International conferenceFox colorings and cocycle invariants of roll-spun knotsOral presentation
- The sixth East Asian School of Knots and Related topics, Jan. 2010, English, 河内 明夫, Nankai University, China, International conferenceApplication of length of quandle 3-cocycle to surface-knot theory[Invited]Invited oral presentation
- 日本数学会秋季総合分科会, Sep. 2009, Japanese, 日本数学会, 大阪大学, Domestic conference5次二面体カンドルの3コサイクルの長さOral presentation
- The first KOOK-TAPU Joint Seminar on Knot Theory and Related Topics, Aug. 2009, English, 河内 明夫, Osaka City University, International conferenceThe triple point number of the 2-twist-spun figure-eight knot[Invited]Invited oral presentation
- Workshop on Topology and Geometry, Jul. 2009, Japanese, 鎌田 聖一, 広島大学, Domestic conference5次二面体カンドルの望月コサイクルの長さとその応用Oral presentation
- 日本数学会年会, Mar. 2009, Japanese, 日本数学会, 東京大学, Domestic conference非自明$2$次元結び目のシート数は$4$以上Oral presentation
- 第6回城崎新人セミナー, Feb. 2009, Japanese, 森 伸吾, 兵庫県豊岡市城崎町, Domestic conference曲面結び目の射影図について[Invited]Invited oral presentation
- 研究集会「4次元トポロジー」, Jan. 2009, Japanese, 鎌田 聖一, 広島大学, Domestic conferenceEvery non-trivial 2-knot needs four sheetsOral presentation
- GThe 5th East Asian School of Knots and Related Topics, Jan. 2009, English, 河内 明夫, 慶州・韓国, International conferenceEvery non-trivial 2-knot needs four sheetsOral presentation
- 研究集会「結び目の数学」, Dec. 2008, Japanese, 大山 淑之, 東京女子大学, Domestic conferenceTriviality of 2-knot with three sheetsOral presentation
- 北陸結び目セミナー「不変量と局所変形」, Nov. 2008, Japanese, 新國 亮, 金沢大学, Domestic conference結び目を5彩色するときに必要な色の数Oral presentation
- Friday seminar on Knot Theory, Nov. 2008, Japanese, 河内 明夫, 大阪市立大学, Domestic conferenceTriviality of 2-knot with three sheets[Invited]Invited oral presentation
- Intelligence of Low Dimensional Topology 兼拡大KOOKセミナー, Oct. 2008, Japanese, 河内 明夫, 大阪市立大学, Domestic conferenceTriviality of 2-knot with one or two sheetsOral presentation
- 日本数学会秋季総合分科会, トポロジー分科会, Sep. 2008, Japanese, 日本数学会, 東京工業大学, Domestic conference5彩色可能な結び目の4色で塗られる射影図Oral presentation
- 夏の学校「低次元トポロジーにおける未解決問題」, Aug. 2008, Japanese, 川村 友美, 名古屋大学, Domestic conference結び目の表示2[Invited]Invited oral presentation
- 夏の学校「低次元トポロジーにおける未解決問題」, Aug. 2008, Japanese, 川村 友美, 名古屋大学, Domestic conferenceカンドルホモロジーと結び目不変量[Invited]Invited oral presentation
- トポロジー・幾何セミナー, Jul. 2008, Japanese, 鎌田 聖一, 広島大学, Domestic conferenceTriviality of 2-knot with one or two sheets[Invited]Invited oral presentation
- 幾何学的視点からの特異点論, Jun. 2008, Japanese, 佐伯 修, 九州大学, Domestic conferenceTriviality of 2-knot with one or two sheetsOral presentation
- トポロジー金曜セミナー, May 2008, Japanese, 佐伯 修, 九州大学, Domestic conferenceシート数1の2次元結び目の自明性[Invited]Invited oral presentation
- 日本数学会トポロジー分科会, Mar. 2008, Japanese, 日本数学会, 近畿大学, Domestic conference三重点数4の3彩色可能な2次元結び目についてOral presentation
- 研究集会「4次元トポロジー」, Feb. 2008, Japanese, 鎌田 聖一, 広島大学, Domestic conferenceNo knotted projective plane has triple point number twoOral presentation
- The Fourth East Asian School of Knots and Related Topics, Jan. 2008, English, 河内 明夫, 東京大学・日本, International conferenceOn tricolorable 2-knots of triple point number fourOral presentation
- International Conference on Topology and its Applications 2007, Dec. 2007, English, 河野 明, 京都大学・日本, International conferenceKnotted projective plane with two triple pointsOral presentation
- Knotting Mathematics and Art, Nov. 2007, English, M. Saito, 南フロリダ大学・アメリカ, International conferenceOn tricolorable 2-knots of triple point number fourOral presentation
- Geometric Topology Conference, Jun. 2007, English, Boju Jiang, 北京大学・中国, International conferenceThe sheet numbers of 2-knotsOral presentation
- Friday Seminar on Knot Theory, Jun. 2007, Japanese, 河内 明夫, 大阪市立大学, Domestic conferenceThe sheet numbers of 2-knots[Invited]Invited oral presentation
■ Research Themes
- 日本学術振興会, 科学研究費助成事業, 基盤研究(C), 神戸大学, 01 Apr. 2022 - 31 Mar. 2025曲面結び目のリスト作成と仮想結び目の不変量の研究
- Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), Osaka University, 01 Apr. 2019 - 31 Mar. 2024Research on 4-dimensional topology from the viewpoint of graphics and quandle theoryカンドルの代数構造に積の演算を組み込んだ代数に関する研究を行なった。このような代数構造は演算の満たすべき公理として様々な候補が考えられる。3価頂点を持つブレイドの一般化の図式に関連した構造が、一つの候補となる。これについては彩色数などの不変量があるが、直接的で幾何的な解釈を与える問題は解決されていない。前年度のフロベニウス代数の公理の図式化では、高次元化として、平面上の3価グラフとその基本変形、3次元空間内の分岐曲面が自然に現れることを見たが、今年度は少し条件を緩めた時に、4次元空間内のブレイド状の分岐曲面を考えることが自然であることがわかった。これは、仮想交点を伴うブレイドが絡み目のモーション群を用いて解釈されることに対応していて、カンドルの余次元2の部分多様体の観点での解釈により近いものといえる。充填を導入することで、佐藤やRourkeによる仮想結び目の4次元空間内のリボントーラスによる解釈のような関係が期待される。 2021年5月19日-21日に京都大学数理解析研究所で研究集会「Intelligence of Low-dimensional Topology」をオンラインで開催した。世話人は大槻知忠(分担者)と秋吉宏尚で、11件の講演と約140名(外国人1名を含む)の参加者あった。2021年11月12日-14日に大阪大学で研究集会「4次元トポロジー」をオンラインで開催した。世話人は鎌田(代表者)、安井弘一(分担者)、松本堯生で、12件の講演と84名(外国人2名を含む)の参加者があった。2021年11月25日-26日に大阪市立大学で研究集会「カンドルと対称空間」をオンラインで開催した。世話人に鎌田、大城佳奈子(分担者)が含まれ、7件の講演があった。
- 日本学術振興会, 科学研究費助成事業, 基盤研究(C), 神戸大学, 01 Apr. 2019 - 31 Mar. 2023曲面結び目の射影図による構成と不変量による分類の研究曲面結び目とは4次元ユークリッド空間に滑らかに埋め込まれた閉曲面のことであり、その射影図とは3次元ユークリッド空間に射影された像で、自己交差集合に上下の交差情報を入れたもののことである。また曲面結び目の3重点数とは、そのすべての射影図にわたる3重点の個数の最小値のことであり、これを基準にして曲面結び目の分類を与えることは、曲面結び目理論の研究において基本的かつ重要なことであると考えられる。 前年度までの研究により、3重点数が4である2次元結び目(閉曲面が2次元球面である場合の曲面結び目)の決定を行ったが、本年度はその証明で用いた手法をさらに整理し精査することにより、2次元球面とは限らない閉曲面の場合に、その3重点数を実現する射影図の自己交差集合がみたすべき必要条件を与えることができた。これを用いるとYashiro氏らによる3重点数2のトーラスの曲面結び目の非存在の結果に対する簡易な別証明を与えることができる。 また、前年度までに行った仮想結び目の3種類の交差多項式に関する一連の結果に加えて、仮想結び目の支持種数(仮想結び目の射影図を実現する閉曲面の種数の最小値)が1の場合に、トーラス上の閉曲線の回転数を利用することにより、その第三交差多項式を精密化することに成功した。これにより、通常の第三交差多項式では区別できなかった仮想結び目の対で、精密化した多項式では区別できるようになるものの存在が期待できる。
- Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), Osaka City University, 01 Apr. 2014 - 31 Mar. 2019Research on 4-dimensional topology from the viewpoint of graphics and quandle theoryFor an immnersed surface-link, which is a closed surface immersed in Euclidean 4-space, the notion of a normal form was introduced and it was proved that any immersed surface-link can be deformed into a normal form. Using a normal form, we obtain a method of describing immersed surface-links bu marked graph diagrams. We also introduced the notion of a ribbon-clasp surface-link as a natural generalization of a ribbon surface-link, and gave a condition for an immersed surface-link to be ribbon-clasp. The tensor product of quandles was defined, and as an application, we gave a method of describing 1-handles attaching to a surface-link. Using the tensor prodocut of a finite quandle, one can easily obtain an invariant of 1-handles attaching to a surface-link.
- 学術研究助成基金助成金/基盤研究(C), Apr. 2016 - Mar. 2019, Principal investigatorCompetitive research funding
- Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (A), Osaka City University, 01 Apr. 2012 - 31 Mar. 2017Studies of knot theory and their applicationsUsing the knot as a key word, we have been working to encourage the development of mathematics in general, with a view of the related physics, chemistry and biology. Based on Osaka City University Mathematics Research Institute as an activity base and based on research cooperation agreements with 8 institutes in East Asia, we aimed to build a research network with Asia. We supported participation in many international or domestic regular meetings such as the satellite knot theory international conference of the Seoul International Congress of Mathematicians. Throughout these meetings, numerous important research results were obtained by a number of knot related researchers including research planning workers, which include research achievements obtaining two patents on the game "Region Select" applying the knot theory and solving a pending issue of 45 years of a ribbon 2-knot by the research representative.
- 学術研究助成基金助成金/基盤研究(C), Apr. 2013 - Mar. 2016, Principal investigatorCompetitive research funding
- Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), 01 Apr. 2009 - 31 Mar. 2014Research on 4-dimensional topology from the viewpoint of graphics and quandle theoryIn order to describe a structure of a genus-2 Lefschetz fibration of a 4-manifold, we introduced a graphical method, called the chart description. Using this method, we obtained a theorem on stabilization of genus-2 Lefschetz fibrations, that is a generalization of a theorem due to D. Auroux, and a theorem due to B. Siebert and G. Tian. A symmetric quandle is a quandle with an additional structure, called a good involution. We introduced the homology theory of a symmetric quandle, and using it, we defined an invariant for surface links in 4-space. The invariant is defined even if the surface link is non-orientable. It can be used for estimation of the minimal triple number of a surface-link.
- Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (C), Nagoya City University, 2010 - 2012THE RESEARCH OF THE STRUCTURES AND INVARIANTS OF STABLE EQUIVALENCE CLASSES OF KNOTS IN THICKENED SURFACESWe defined the quandles of the stable equivalence classes of knots in thickened surfaces (twisted knots) and gave the geometric interpretation of the quandles of twisted knots. We also introduced the multivariable polynomial invariants and the index polynomials of twisted knots and showed that they are useful to distinguish twisted knots. We coded the computer programs to makes the list of twisted knot diagrams and to calculate the invariants of twisted knots. Using the programs, we constructed thetable of twisted knots.
- Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (A), Osaka City University, 2009 - 2011Studies of Knot TheoryKnot theory is related to most advanced modern mathematics and also to many research fields in science. The purpose of this program was to develop、in a national scale、both education and study of an extensive knot theory on the basis of the accomplishments of the 21 COE program of Osaka City Advanced Mathematical institute. The support project of international and domestic meetings was carried out steadily、and many new findings on knot theory could be obtained. Among such research activities、unique studies of knot theory such as the publication of an English book of teaching and learning methods of knot theory in school mathematics and three patent applications of knot theory were born.
- 科学研究費補助金/若手研究(B), 2010, Principal investigatorCompetitive research funding
- 科学研究費補助金/基盤研究(C), 2009Competitive research funding
- Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (C), Chiba University, 2005 - 2008Applications of the Ricci flow tedimentional differential toppologリッチ流の4次元での挙動が不安定であることの経験が得られたが、現時点で4次元における特異点生成のモデルは得られていない.しかし、リッチ流が収束するジェネリッチな構造である双曲構造と関連して、1-3価グラフから得られるある線形空間の次元を評価する公式や、双曲構造と数論との関連、また4次元中の曲面結ぴ目のある種の彩色数に関する結果が得られている.
- 科学研究費補助金/若手研究(B), 2006, Principal investigatorCompetitive research funding
- Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (C), Chiba University, 2002 - 2003Topological study of Engel structures and its characteristic foliationsAn Engel structure is a maximally non-integrable 2-dimensional plane field on a 4-dimensional manifold. In this research we investigated global properties of Engel structures from the viewpoint of topology. In particular, we paid attention to the characteristic 1-dimensional foliations canonically associated to Engel structures. First, we considered the following problem posed by Gershkovich : Does there exist an Engel structure on the 4-dimensional Euclidean space whose characteristic foliation admits a compact leaf ? We affirmatively solved this problem by constructing a concrete example. We also applied the construction to obtaining Engel structures on other open 4-manifolds. This result was published in Bulletin of the Australian Mathematical Society. Next, P.Walczak, the foreign joint investigator of this research, constructed an Engel structure using an Anosov flow. The head investigator remarked that this Engel structure is essentially new. Namely, it is not isotopic to any other known examples. Thirdly, we sought 1-dimensional transversely parallelizable foliations on 4-dimensional manifolds which cannot be topologically conjugate to the characteristic foliation of any Engel structure. It is known that a characteristic foliation admits a tangential projective structure and transverse contact structure. We observed the following fact : If a compact leaf of a characteristic foliation has finite holonomy, then the projective. structure of the leaf is not affine. Using this fact we found a l-dimensional transversely parallelizable foliation which is not topologically conjugate to the characteristic foliation of any Engel structure. Finally, we initiated the study of generalizing the rigidity property of characteristic foliations of Engel structures to the cases of higher dimensional plane fields.
