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Cyclotomic KLR algebras in type C: cellularity and blocks

Research Project

Project/Area Number 20K22316
Research Category

Grant-in-Aid for Research Activity Start-up

Allocation TypeMulti-year Fund
Review Section 0201:Algebra, geometry, analysis, applied mathematics,and related fields
Research InstitutionOkinawa Institute of Science and Technology Graduate University

Principal Investigator

Speyer Liron  沖縄科学技術大学院大学, 表現論と代数的組合せ論ユニット, 准教授(Assistant Professor) (00873762)

Project Period (FY) 2020-09-11 – 2023-03-31
Project Status Completed (Fiscal Year 2022)
Budget Amount *help
¥2,860,000 (Direct Cost: ¥2,200,000、Indirect Cost: ¥660,000)
Fiscal Year 2021: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
Fiscal Year 2020: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
KeywordsCyclotomic KLR algebras / Hecke algebras / Schurian-finiteness / Specht modules / Cellular algebras / Quiver Hecke algebras / Representation theory / KLR algebras
Outline of Research at the Start

In joint work with Ariki and Park, I have introduced families of Specht modules over KLR algebras in (finite and affine) type C, and highlighted their importance in subsequent work. We expect that these algebras are also cellular, and that our Specht modules coincide with the cell modules. The major goals of this project are to prove that these algebras are indeed cellular, and subsequently use our techniques and results to further study their block structure. These results will open the door to further study of these algebras, including their decomposition numbers.

Outline of Final Research Achievements

We determined the Schurian-finiteness, or equivalently the tau-tilting finiteness, of blocks of type A Iwahori-Hecke algebras, in a preprint (arXiv:2112.11148) submitted for publication. Our main result is that blocks are Schurian-finite if and only if they have finite representation type (known to be the case if and only if they have weight 0 or 1). This project made use of a great breadth of tools, both existing and newly developed for our work.
We've also developed 2 algorithms for computing graded decomposition numbers for cyclotomic KLR algebras R\Lambda_n in type C, and computed all such graded decomposition matrices in level 1, for n<13. In this same project, we also computed the submodule structure of Specht modules in characteristic 0 for n<11, and obtained the first example of characteristic 0 graded decomposition numbers that are not given by the corresponding canonical basis coefficients. The paper is being written up, and we aim to have a preprint submitted by the autumn.

Academic Significance and Societal Importance of the Research Achievements

Schurian-finiteness is a property which many researchers in finite-dimensional algebras seek to determine for algebras.
The KLR algebras arose from categorification of quantum groups and are studied a lot recently as part of a broader program of categorification. Many open questions remain.

Report

(4 results)
  • 2022 Annual Research Report   Final Research Report ( PDF )
  • 2021 Research-status Report
  • 2020 Research-status Report
  • Research Products

    (15 results)

All 2022 2021 Other

All Int'l Joint Research (4 results) Journal Article (2 results) (of which Int'l Joint Research: 1 results,  Peer Reviewed: 1 results,  Open Access: 1 results) Presentation (9 results) (of which Int'l Joint Research: 1 results,  Invited: 6 results)

  • [Int'l Joint Research] University of East Anglia(英国)

    • Related Report
      2022 Annual Research Report
  • [Int'l Joint Research] Washington & Jefferson College(米国)

    • Related Report
      2022 Annual Research Report
  • [Int'l Joint Research] University of Sydney(オーストラリア)

    • Related Report
      2022 Annual Research Report
  • [Int'l Joint Research] Osaka University(日本)

    • Related Report
      2022 Annual Research Report
  • [Journal Article] Decomposable Specht modules indexed by bihooks II2021

    • Author(s)
      Robert Muth, Liron Speyer, Louise Sutton
    • Journal Title

      Algebras and Representation Theory

      Volume: In press Issue: 1 Pages: 241-280

    • DOI

      10.1007/s10468-021-10093-3

    • Related Report
      2021 Research-status Report
    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Journal Article] Strong Gelfand subgroups of $F \wr S_n$2021

    • Author(s)
      Can Mahir Bilen、She Yiyang、Speyer Liron
    • Journal Title

      International Journal of Mathematics

      Volume: 32 Issue: 02 Pages: 2150010-2150010

    • DOI

      10.1142/s0129167x21500105

    • Related Report
      2020 Research-status Report
  • [Presentation] Schurian-infinite blocks of type A Hecke algebras2022

    • Author(s)
      Liron Speyer
    • Organizer
      York Algebra Seminar
    • Related Report
      2022 Annual Research Report
    • Invited
  • [Presentation] Schurian-infinite blocks of type A Hecke algebras2022

    • Author(s)
      Liron Speyer
    • Organizer
      Conference on Algebraic Representation Theory 2022
    • Related Report
      2022 Annual Research Report
    • Invited
  • [Presentation] Schurian-infinite blocks of type A Hecke algebras2022

    • Author(s)
      Liron Speyer
    • Organizer
      MSJ Autumn Meeting 2022
    • Related Report
      2022 Annual Research Report
    • Int'l Joint Research
  • [Presentation] The representation theory of type A Iwahori-Hecke algebras II2022

    • Author(s)
      Liron Speyer
    • Organizer
      Silver workshop V: Complex Geometry and related topics, OIST
    • Related Report
      2022 Annual Research Report
    • Invited
  • [Presentation] Graded decomposition matrices for type C KLR algebras2022

    • Author(s)
      Liron Speyer
    • Organizer
      Representation Theory, Combinatorics and Geometry, National University of Singapore
    • Related Report
      2022 Annual Research Report
    • Invited
  • [Presentation] Schurian-infinite blocks of type A Hecke algebras2022

    • Author(s)
      Liron Speyer
    • Organizer
      Physical Algebra and Combinatorics Seminar, OCAMI
    • Related Report
      2021 Research-status Report
    • Invited
  • [Presentation] Semisimple Specht modules indexed by bihooks2021

    • Author(s)
      Liron Speyer
    • Organizer
      London Algebra Colloquium
    • Related Report
      2021 Research-status Report
    • Invited
  • [Presentation] Semisimple Specht modules indexed by bihooks2021

    • Author(s)
      Liron Speyer
    • Organizer
      Algebraic Lie Theory Seminar, University of Colorado Boulder
    • Related Report
      2020 Research-status Report
  • [Presentation] Semisimple Specht modules indexed by bihooks2021

    • Author(s)
      Liron Speyer
    • Organizer
      London algebra colloquium
    • Related Report
      2020 Research-status Report

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Published: 2020-09-29   Modified: 2024-01-30  

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