Takuya Takeishi

Assistant Professor, Kyoto Institute of Technology

e-mail: takeishi at kit.ac.jp

Reserch interest: Operator algebras from number theory (Bost-Connes systems, semigroup C*-algebras arising from number theory), KMS-states, groupoid C*-algebras.

Supported by JSPS KAKENHI Grant Number JP19K14551 (2019-2023) 
Previous KAKENHI

Research map

Schedules

5-7 September 2022 RIMS Conference, Kyoto, Japan
12-17 September 2022 MSJ Autumn Meeting 2022, Sapporo, Japan
6-13 October 2022 Tokyo, Japan
29 October - 21 November 2022 Glasgow, UK
5-6 December 2022 Kyushu, Japan
23-25 January 2023 RIMS Conference, Kyoto, Japan
16-18 March 2023 MSJ Spring Meeting 2023, Tokyo, Japan
27-30 March 2023 Low dimensional topology and number theory XIV, Kyushu, Japan

Courses

Past Courses

Publications

  1. T. Takeishi, On Nuclearity of C*-algebras of Fell Bundles over Étale Groupoids, Publications of the Research Institute for Mathematical Sciences 50, no.2, 251-268. (2014) published version arXiv version
  2. T. Takeishi, Irreducible Representations of Bost-Connes systems, Journal of Noncommutative Geometry 10, no. 3, 889-906. (2016) published version arXiv version
    (Note : For arXiv version, the current version is 2. Several mistakes of notations are revised and section numbers are changed.)
  3. T. Takeishi, Bost-Connes systems for local fields of characteristic zero, International Mathematics Research Notices IMRN 2018, no. 7, 2052-2069 (2018). published version arXiv version
  4. T. Takeishi, Primitive ideals and K-theoretic approach to Bost-Connes systems, Advances in Mathematics 302, 1069-1079. (2016) published version arXiv version
    (Note : For arXiv version, the current version is 2. Proposition 3.6, Remark 3.13, and several minor revisions are added.)
  5. Y. Kubota and T. Takeishi, Reconstructing the Bost--Connes semigroup actions from K-theory, Advances in Mathematics 366 (2020) published version arXiv version
    (Page number will be added later.)
  6. C. Bruce, M. Laca and T. Takeishi, Partition functions as C*-dynamical invariants and actions of congruence monoids, Communications in Mathematical Physics 382, no.2, 1165–1203. (2021) published version arXiv:1911.00793
    (Note : For arXiv version, the current version is 2. )
  7. C. Bruce and T. Takeishi, C*-dynamical invariants and Toeplitz algebras of graphs (2021), to appear in J. Operator Theory arXiv:2103.02816
  8. T. Takeishi, Limits of KMS states on Toeplitz algebras of finite graphs (2021), to appear in J. Operator Theory arXiv:2108.08431
  9. C. Bruce and T. Takeishi, Constructing number field isomorphisms from *-isomorphisms of certain crossed product C*-algebras (2022), arXiv:2203.08690
  10. C. Bruce and T. Takeishi, On the C*-algebra associated with the full adele ring of a number field (2022), arXiv:2209.10857

Other articles

  1. 武石拓也,作用素環論と数論,「数理科学」2019年12月号掲載

Talks

  1. On Nuclearity of C*-algebras of Fell Bundles over Étale Groupoids, Operator Algebra Seminar, Tokyo, April, 2013
  2. On Nuclearity of C*-algebras of Fell Bundles over Étale Groupoids, Recent Developments in Operator Algebras, Kyoto, September, 2013
  3. On Class Field Theory, Conference of Functional Analysis, Kusatsu, September, 2013
  4. On Nuclearity of C*-algebras of Fell Bundles over Étale Groupoids, MSJ Autumn Meeting 2013, Ehime, September, 2013
  5. Bost-Connes system for local fields of characteristic zero, C*-algebra seminar, Oslo, January, 2014
  6. Bost-Connes system for local fields of characteristic zero, Operator Algebra Seminar, Tokyo, April, 2014
  7. Bost-Connes system for local fields of characteristic zero, ICM Satellite Conference on Operator Algebra and Applications, Korea, August, 2014
  8. On Bost-Connes Systems, Conference of Functional Analysis, Gifu, August, 2014
  9. Bost-Connes system for local fields of characteristic zero, MSJ Autumn Meeting 2014, Hiroshima, September, 2014
  10. Bost-Connes system for local fields of characteristic zero, The Second China-Japan Conference on Noncommutative Geometry and K-Theory, Okinawa, October, 2014
    Slides
  11. Irreducible Representations of Bost-Connes systems, Number theory and non-commutative geometry, Bonn, November, 2014
    Video on Youtube
  12. Irreducible Representations of Bost-Connes systems, Workshop on Operator Theory and Operator Algebras, Tokyo, December, 2014
  13. Irreducible Representations of Bost-Connes systems, Kyoto Operator Algebra Seminar, Kyoto, March, 2015
  14. Irreducible Representations of Bost-Connes systems, Oberseminar, Münster, June, 2015
  15. Irreducible Representations of Bost-Connes systems, Oberwolfach, June, 2015
  16. Primitive Ideals of Bost-Connes C*-algebras, Geometry and Analysis seminar, London, September, 2015
  17. On the classification problem of Bost-Connes systems, Operator Algebra Seminar, Copenhagen, October, 2015
  18. Primitive ideals and K-theoretic approach to Bost-Connes systems, Münster, December, 2015
  19. Primitive ideals and K-theoretic approach to Bost-Connes systems, Victoria, March, 2016
  20. Primitive ideals and K-theoretic approach to Bost-Connes systems, Kyoto Operator Algebra Seminar, Kyoto, July, 2016
  21. On the condition C^*_(G)=C^*_r(G) for étale groupoids (after R. Willett), Conference of Functional Analysis, Kusatsu, August, 2016
  22. Primitive ideals and K-theoretic approach to Bost-Connes systems, Recent Developments in Operator Algebras, Kyoto, September, 2016
  23. Primitive ideals and K-theoretic approach to Bost-Connes systems, MSJ Autumn Meeting 2016, Osaka, September, 2013
  24. On the classification of Bost-Connes C*-algebras, Geometry and Analysis seminar, London, January, 2017
  25. On the classification problem of Bost-Connes systems, Analysis Seminar, Sapporo, 2017
  26. Basics of K-theory, Conference of Functional Analysis, Nara, August, 2017
  27. Reconstructing the Bost-Connes semigroup actions from K-theory, Recent Developments in Operator Algebras, Kyoto, September, 2017
  28. Reconstructing the Bost-Connes semigroup actions from K-theory, Facets of Irreversibility: Inverse Semigroups, Groupoids, and Operator Algebras, Oslo, Norway, December, 2017
  29. Reconstructing the Bost-Connes semigroup actions from K-theory, Mathematical study on topological phases, RIMS, Kyoto, Japan, January 2018
  30. Reconstructing the Bost-Connes semigroup actions from K-theory, MSJ Spring Meeting 2018, Tokyo, Japan, March, 2018
  31. Reconstructing the Bost-Connes semigroup actions from K-theory. I, Operator theory seminar, Victoria, Canada, September, 2018
  32. Reconstructing the Bost-Connes semigroup actions from K-theory. II, Operator theory seminar, Victoria, Canada, September, 2018
  33. Reconstructing the Bost-Connes semigroup actions from K-theory, Geometry and Analysis Seminar, London, UK, October, 2018
  34. Reconstructing the Bost-Connes semigroup actions from K-theory. I, Workshop on Operator Theory and Operator Algebras, Shizuoka, December, 2018
  35. Reconstructing the Bost-Connes semigroup actions from K-theory. II, Workshop on Operator Theory and Operator Algebras, Shizuoka, December, 2018
  36. Reconstructing the Bost-Connes semigroup actions from K-theory, Young mathematicians workshop on algebraic, geometric, and analytic aspects of K theory and vector bundles, Okinawa, August, 2019
  37. C*-dynamical invariants for actions of congruence monoids (in preparation), Operator theory seminar, Victoria, Canada, September, 2019
  38. Partition functions as C*-dynamical invariants and actions of congruence monoids, Kyoto Operator Algebra Seminar, Kyoto, 2019
  39. Partition functions as C*-dynamical invariants and actions of congruence monoids, 作用素環の分類理論における新展開, RIMS, Kyoto, Japan, 2020
  40. Partition functions as C*-dynamical invariants and actions of congruence monoids, MSJ Spring Meeting 2020, Tokyo, March, 2020
    (This conference is canceled, but this talk shall be deemed held. See here (Japanese))
  41. Partition functions as C*-dynamical invariants and actions of congruence monoids, Tokyo-Kyoto Operator Algebra Seminar, Online, May, 2020
  42. Operator Algebras and Number Theory, Conference of Functional Analysis, Online, September, 2020
  43. Partition functions as C*-dynamical invariants and actions of congruence monoids, CMS Winter Meeting 2020, Online (Canada), December, 2020
  44. Partition functions as C*-dynamical invariants and actions of congruence monoids, 作用素環と量子力学系, Online (RIMS Kyoto), February, 2021
  45. C*-dynamical invariants and Toeplitz algebras of graphs (part 2 of 2), Operator Algebra and Noncommutative Geometry seminar, Online (Wollongong, Australia), March, 2021
  46. KMS states of Toeplitz algebras of graphs, Tokyo-Kyoto Operator Algebra Seminar, Online, June, 2021
  47. KMS states of Toeplitz algebras of graphs, 第60回実函数論・函数解析学合同シンポジウム, Online, September, 2021
  48. Constructing number field isomorphisms from *-isomorphisms of certain crossed product C*-algebras, Kyoto Operator Algebra Seminar, Kyoto, April, 2022
  49. Constructing number field isomorphisms from *-isomorphisms of certain crossed product C*-algebras, MSJ Autumn Meeting 2022, Sapporo, September, 2022
  50. Constructing number field isomorphisms from *-isomorphisms of certain crossed product C*-algebras, Tokyo Operator Algebra Seminar, October, October, 2022
  51. Rigidity theorems of certain classes of C*-algebras from number theory I-III, 作用素環論における群作用と数理物理の関連, Kyoto, January, 2023

Poster Sessions

  1. Irreducible Representations of Bost-Connes systems, Future directions for non-commutative geometry, Bonn, December, 2014

C.V.

March 2011 Bachelor of Sciences, University of Tokyo
November 2012 - March 2016 FMSP fellow
March 2013 Master of Mathematical Sciences, the University of Tokyo (Supervisor: Yasuyuki Kawahigashi)
April 2013 - March 2016 JSPS Fellow (DC1)
March 2016 Ph.D. of Mathematical Sciences, the University of Tokyo (Supervisor: Yasuyuki Kawahigashi)
April 2016 - March 2017 Program-Specific Researcher (Fujiwara's grant), Department of Mathematics, Kyoto University
April 2017 - March 2018 Researcher (part-time), Research Institute for Mathematical Sciences, Kyoto University
April 2017 - August 2017 Lecturer (part-time), Institute for Liberal Arts and Sciences, Kyoto University
April 2018 - Assistant Professor, Kyoto Institute of Technology