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Structure Analysis of a Category of Cohen--Macaulay Modules by the Representation Scheme

Research Project

Project/Area Number 18K13399
Research Category

Grant-in-Aid for Early-Career Scientists

Allocation TypeMulti-year Fund
Review Section Basic Section 11010:Algebra-related
Research InstitutionNational Institute of Technology (KOSEN), Kure College

Principal Investigator

Hiramatsu Naoya  呉工業高等専門学校, 自然科学系分野, 准教授 (20612039)

Project Period (FY) 2018-04-01 – 2023-03-31
Project Status Completed (Fiscal Year 2022)
Budget Amount *help
¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000)
Fiscal Year 2020: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000)
Fiscal Year 2019: ¥520,000 (Direct Cost: ¥400,000、Indirect Cost: ¥120,000)
Fiscal Year 2018: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000)
KeywordsCohen-Macaulay加群 / 表現型 / module variety / 関手圏 / 極大Cohen-Macaulay加群 / 加算表現型 / 退化 / 加算CM表現型 / Krull-Gabriel次元 / 極大コーエン・マコーレー加群 / 次数付き極大コーエン・マコーレー加群 / コーエン・マコーレー加群 / 表現スキーム
Outline of Final Research Achievements

We define a topological structure for the set of isomorphism classes of MCM modules based on the degeneration relation of the modules and classify the irreducible closed subsets by the topology. The representation scheme of the graded MCM modules is considered. We show that there are only a finite number of isomorphism classes of the graded MCM modules when the rank is fixed. We also calculate the Krull-Gabriel dimension of the functor category of the (stable) category of MCM modules over hypersurfaces of countable CM representation type. We show that the Krull-Gabriel dimension is 0 if the hypersurface is of finite CM representation type and that is 2 if the hypersurface is of countable but not finite CM representation type.

Academic Significance and Societal Importance of the Research Achievements

MCM加群の退化の関係による位相構造の考察は、幾何学的な性質によったMCM加群の分類例が得られ(例えば基礎環が有限CM表現型ではなくても有限個の既約閉集合による分解が得られる)、分類理論に新しい視点を与える。次数付きMCM加群の表現スキームの考察は幾何学的性質からある種のMCM加群の有限性を与えることができ、表現スキームの有効性やその可能性を示した結果である。さらにクルル-ガブリエル次元の計算はそれ自体が計算することが困難な量であるため、非自明な例を与えたことは重要である。いずれもMCM加群の表現論に寄与する結果であると考えられる。

Report

(6 results)
  • 2022 Annual Research Report   Final Research Report ( PDF )
  • 2021 Research-status Report
  • 2020 Research-status Report
  • 2019 Research-status Report
  • 2018 Research-status Report
  • Research Products

    (17 results)

All 2022 2021 2020 2019 2018 Other

All Journal Article (6 results) (of which Open Access: 1 results,  Peer Reviewed: 2 results) Presentation (5 results) (of which Int'l Joint Research: 2 results,  Invited: 1 results) Remarks (5 results) Funded Workshop (1 results)

  • [Journal Article] Krull-Gabriel dimension of Cohen-Macaulay modules over hypersurfaces of type (A_∞)2022

    • Author(s)
      Naoya Hiramatsu
    • Journal Title

      Proceedings of the 53rd Symposium on Ring Theory and Representation Theory

      Volume: 53 Pages: 80-86

    • Related Report
      2021 Research-status Report
    • Open Access
  • [Journal Article] Geometry of varieties for graded maximal Cohen--Macaulay modules2021

    • Author(s)
      Hiramatsu Naoya
    • Journal Title

      manuscripta mathematica

      Volume: - Issue: 1-2 Pages: 377-384

    • DOI

      10.1007/s00229-021-01282-x

    • Related Report
      2020 Research-status Report
    • Peer Reviewed
  • [Journal Article] A topology on the set of isomorphism classes of maximal Cohen--Macaulay modules2020

    • Author(s)
      Hiramatsu Naoya、Takahashi Ryo
    • Journal Title

      Proceedings of the American Mathematical Society

      Volume: 148 Issue: 6 Pages: 2359-2369

    • DOI

      10.1090/proc/14965

    • Related Report
      2019 Research-status Report
    • Peer Reviewed
  • [Journal Article] A remark on graded countable Cohen-Macaulay representation type2020

    • Author(s)
      Hiramatsu Naoya
    • Journal Title

      Proceedings of the 52nd Symposium on Ring Theory and Representation Theory

      Volume: 52 Pages: 21-25

    • Related Report
      2019 Research-status Report
  • [Journal Article] A note on graded countable Cohen-Macaulay representation type2020

    • Author(s)
      Hiramatsu Naoya
    • Journal Title

      Proceedings of the 41st Japan Symposium on Commutative Algebra

      Volume: 41 Pages: 14-18

    • Related Report
      2019 Research-status Report
  • [Journal Article] Irreducible components of the topological space of Cohen-Macaulay modules2019

    • Author(s)
      平松直哉, 高橋亮
    • Journal Title

      第40回可換環論シンポジウム報告集

      Volume: 40 Pages: 71-78

    • Related Report
      2018 Research-status Report
  • [Presentation] Krull-Gabriel dimension of Cohen--Macaulay modules over $(A_\infty)$-singularities2021

    • Author(s)
      Naoya Hiramatsu
    • Organizer
      東京可換環論セミナー
    • Related Report
      2021 Research-status Report
    • Invited
  • [Presentation] Krull-Gabriel dimension of Cohen-Macaulay modules over hypersurfaces of type (A_∞)2021

    • Author(s)
      Naoya Hiramatsu
    • Organizer
      第53回環論および表現論シンポジウム
    • Related Report
      2021 Research-status Report
  • [Presentation] A remark on graded countable Cohen-Macaulay representation type2019

    • Author(s)
      Hiramatsu Naoya
    • Organizer
      The Eighth China - Japan - Korea International Symposium on Ring Theory Nagoya, JAPAN (2019)
    • Related Report
      2019 Research-status Report
    • Int'l Joint Research
  • [Presentation] A note on graded countable Cohen-Macaulay representation type2019

    • Author(s)
      Hiramatsu Naoya
    • Organizer
      The 41st Japan Symposium on Commutative Algebra
    • Related Report
      2019 Research-status Report
    • Int'l Joint Research
  • [Presentation] Irreducible components of the topological space of Cohen-Macaulay modules2018

    • Author(s)
      平松直哉, 高橋亮
    • Organizer
      第40回可換環論シンポジウム
    • Related Report
      2018 Research-status Report
  • [Remarks] 岡山可換代数表現セミナー(OSCAR)

    • URL

      https://sites.google.com/view/oscarmath2021/oscar-home

    • Related Report
      2022 Annual Research Report
  • [Remarks] NaoyaHIRAMATSU

    • URL

      https://www.kure-nct.ac.jp/department/g/original/hiramatsu/index.html

    • Related Report
      2022 Annual Research Report 2021 Research-status Report
  • [Remarks] 岡山可換代数表現セミナー

    • URL

      https://sites.google.com/view/oscarmath2021/oscar-home

    • Related Report
      2021 Research-status Report
  • [Remarks] Naoya HIRAMASTU

    • URL

      https://www.kure-nct.ac.jp/department/g/original/hiramatsu/index.html

    • Related Report
      2020 Research-status Report
  • [Remarks] Naoya HIRAMATSU

    • URL

      https://www.kure-nct.ac.jp/department/g/original/hiramatsu/index.html

    • Related Report
      2019 Research-status Report 2018 Research-status Report
  • [Funded Workshop] The 41st Japan Symposium on Commutative Algebra2019

    • Related Report
      2019 Research-status Report

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Published: 2018-04-23   Modified: 2024-01-30  

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