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On the classification problem of Bost-Connes systems

Research Project

Project/Area Number 17H06785
Research Category

Grant-in-Aid for Research Activity Start-up

Allocation TypeSingle-year Grants
Research Field Basic analysis
Research InstitutionKyoto Institute of Technology (2018)
Kyoto University (2017)

Principal Investigator

Takeishi Takuya  京都工芸繊維大学, 基盤科学系, 助教 (20784490)

Project Period (FY) 2017-08-25 – 2019-03-31
Project Status Completed (Fiscal Year 2018)
Budget Amount *help
¥2,730,000 (Direct Cost: ¥2,100,000、Indirect Cost: ¥630,000)
Fiscal Year 2018: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
Fiscal Year 2017: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
Keywords作用素環論 / C*-環論 / Bost--Connes系 / K-理論 / KMS状態 / 非可換幾何学 / C*-環の分類 / 解析学 / 代数学
Outline of Final Research Achievements

The Bost--Connes C*-algebras are operator algebras coming from number fields. The classification problem of the Bost--Connes C*-algebras has been an important open problem. In this research, we have completely solved this problem. Concretely, we proved that for two number fields K and L, if two Bost--Connes C*-algebras A_K, A_L are isomporphic, then K and L are isomorphic. In addition, we worked on another type of C*-algebras coming from number fields. For this type of C*-algebras, we are writing an article on KMS-states.

Academic Significance and Societal Importance of the Research Achievements

作用素環の同型・非同型を決定することは作用素環論の根源的な課題であり,今回得られた結果は作用素環論として非常に興味深い結果である.それにとどまらず,作用素環論と数論の2つの分野の分野横断的な研究(特に作用素環論の数論への応用)の可能性を感じさせる結果でもある.今回の結果を通じて得られた代数体の不変量に関する研究など,後に続く重要な研究課題が同時に生まれている.総合して,数学の様々な側面から見て価値を持つ研究結果が得られたと考えている.

Report

(3 results)
  • 2018 Annual Research Report   Final Research Report ( PDF )
  • 2017 Annual Research Report
  • Research Products

    (9 results)

All 2018 2017 Other

All Int'l Joint Research (2 results) Journal Article (1 results) (of which Peer Reviewed: 1 results) Presentation (4 results) (of which Int'l Joint Research: 1 results,  Invited: 2 results) Remarks (2 results)

  • [Int'l Joint Research] University of Victoria(カナダ)

    • Related Report
      2018 Annual Research Report
  • [Int'l Joint Research] Queen Mary University of London(英国)

    • Related Report
      2018 Annual Research Report
  • [Journal Article] Reconstructing the Bost--Connes semigroup actions from K-theory2017

    • Author(s)
      Y. Kubota and T. Takeishi
    • Journal Title

      arXiv:1709.03281

      Volume: -

    • Related Report
      2017 Annual Research Report
    • Peer Reviewed
  • [Presentation] Reconstructing the Bost-Connes semigroup actions from K-theory2018

    • Author(s)
      Yosuke Kubota, Takuya Takeishi
    • Organizer
      作用素論・作用素環論研究集会2018
    • Related Report
      2018 Annual Research Report
    • Invited
  • [Presentation] Reconstructing the Bost-Connes semigroup actions from K-theory2018

    • Author(s)
      武石 拓也
    • Organizer
      Mathematical study on topological phases, RIMS, Kyoto, Japan
    • Related Report
      2017 Annual Research Report
    • Invited
  • [Presentation] Reconstructing the Bost-Connes semigroup actions from K-theory2018

    • Author(s)
      武石 拓也
    • Organizer
      MSJ Spring Meeting 2018, Tokyo, Japan
    • Related Report
      2017 Annual Research Report
  • [Presentation] Reconstructing the Bost-Connes semigroup actions from K-theory2017

    • Author(s)
      T. Takeishi
    • Organizer
      Facets of Irreversibility: Inverse Semigroups, Groupoids, and Operator Algebras, Oslo, Norway
    • Related Report
      2017 Annual Research Report
    • Int'l Joint Research
  • [Remarks] 武石研究室website

    • URL

      http://www.cis.kit.ac.jp/~takeishi/

    • Related Report
      2018 Annual Research Report
  • [Remarks] Takuya Takeishi

    • URL

      http://www.cis.kit.ac.jp/~takeishi/

    • Related Report
      2017 Annual Research Report

URL: 

Published: 2017-08-25   Modified: 2020-03-30  

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