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The embedding structure, defining ideals and the projective m-normality of projective varieties

Research Project

Project/Area Number 26400041
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeMulti-year Fund
Section一般
Research Field Algebra
Research InstitutionYokohama National University

Principal Investigator

NOMA ATSUSHI  横浜国立大学, 大学院環境情報研究院, 教授 (90262401)

Project Period (FY) 2014-04-01 – 2017-03-31
Project Status Completed (Fiscal Year 2016)
Budget Amount *help
¥4,680,000 (Direct Cost: ¥3,600,000、Indirect Cost: ¥1,080,000)
Fiscal Year 2016: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
Fiscal Year 2015: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
Fiscal Year 2014: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
Keywords射影多様体 / 射影埋め込み / 線形射影 / 定義方程式 / 斉次イデアル / m-正規性 / カステルヌーボマンフォード正則数 / m正規性 / カステルヌーボ-マンフォード正則数 / 射影埋込み
Outline of Final Research Achievements

We studied the relation between the embedding structute of projective varieties and their defining equations. For a projective variety X, a point of the projective space is called a nonbirational center of X if the linear projection from it induces a nonbirational map onto its image. By B(X) and C(X), we denote the set of nonbirational centers outside of X and inside of X respectively. We call B(X) and C(X) Segre locus and inner Segre locus respectively. In this study, first we give a characterization of a projective variety X with nonempty B(X) and C(X). As one of applications of this result, we have improved the result on Castelnuovo-Mumford regularity for smooth X of codimension e and degree d by showing that the regularity is at most e(d-e)+1. Second we show that the Castelnuovo-Mumford regularity of X with 1-dimensional C(X) is at most d-e+1. Moreover, as an application of these studies, we have a result of maximal minors of a matrix with homogeneous linear forms as entries.

Report

(4 results)
  • 2016 Annual Research Report   Final Research Report ( PDF )
  • 2015 Research-status Report
  • 2014 Research-status Report
  • Research Products

    (11 results)

All 2017 2016 2015 2014

All Journal Article (5 results) (of which Peer Reviewed: 4 results,  Acknowledgement Compliant: 4 results,  Open Access: 1 results) Presentation (6 results) (of which Invited: 4 results)

  • [Journal Article] Projective varieties with nonbirational linear projections and applications2017

    • Author(s)
      Atsushi Noma
    • Journal Title

      Transactions of the American Mathematical Society

      Volume: 印刷中

    • Related Report
      2016 Annual Research Report
    • Peer Reviewed / Acknowledgement Compliant
  • [Journal Article] Castelnuovo-Mumford regularity of projected Roth varieties2016

    • Author(s)
      Atsushi Noma
    • Journal Title

      Journal of Algebra

      Volume: 466 Pages: 153-168

    • DOI

      10.1016/j.jalgebra.2016.06.005

    • Related Report
      2016 Annual Research Report
    • Peer Reviewed / Acknowledgement Compliant
  • [Journal Article] 特殊な線形射影を持つ射影多様体とその応用2015

    • Author(s)
      野間 淳
    • Journal Title

      第60回代数学シンポジウム報告集

      Volume: - Pages: 50-64

    • Related Report
      2015 Research-status Report
    • Acknowledgement Compliant
  • [Journal Article] Maximal minors of a matrix with linear form entries2015

    • Author(s)
      Hiroya Ito, Atsushi Noma, Masahiro Ohno
    • Journal Title

      Linear and Multilinear algebra

      Volume: 印刷中 Issue: 8 Pages: 1599-1606

    • DOI

      10.1080/03081087.2014.959516

    • Related Report
      2014 Research-status Report
    • Peer Reviewed / Open Access / Acknowledgement Compliant
  • [Journal Article] Generic inner projections of projective varieties and an application to the positivity of double point divisors2014

    • Author(s)
      Atsushi Noma
    • Journal Title

      Transactions of the American Mathematical Society

      Volume: 366(9) Pages: 4603-4623

    • Related Report
      2014 Research-status Report
    • Peer Reviewed
  • [Presentation] Defining equations of birational-divisors of conical scrolls2017

    • Author(s)
      野間 淳
    • Organizer
      農工大数学セミナー 2017
    • Place of Presentation
      東京農工大学小金井キャンパス
    • Year and Date
      2017-03-21
    • Related Report
      2016 Annual Research Report
    • Invited
  • [Presentation] Base-point-freeness of double-point divisors of smooth birational-divisors on conical rational scrolls2017

    • Author(s)
      野間 淳
    • Organizer
      日本大学特異点セミナー
    • Place of Presentation
      日本大学文理学部
    • Year and Date
      2017-01-23
    • Related Report
      2016 Annual Research Report
  • [Presentation] Regularity of projected Roth varieties2016

    • Author(s)
      野間 淳
    • Organizer
      日本数学会2016年度年会代数学分科会
    • Place of Presentation
      筑波大学
    • Year and Date
      2016-03-17
    • Related Report
      2015 Research-status Report
  • [Presentation] Nonbirational centers of linear projections of projective varieties2016

    • Author(s)
      野間 淳
    • Organizer
      代数幾何ミニ研究集会
    • Place of Presentation
      埼玉大学
    • Year and Date
      2016-03-11
    • Related Report
      2015 Research-status Report
    • Invited
  • [Presentation] Base-point-freeness of double-point divisors of smooth birational-divisors on conical rational scrolls2016

    • Author(s)
      野間 淳
    • Organizer
      研究集会「代数曲線・曲面とその周辺」(大渕先生還暦記念集会)
    • Place of Presentation
      大阪大学理学部
    • Related Report
      2016 Annual Research Report
    • Invited
  • [Presentation] 特殊な線形射影を持つ射影多様体とその応用2015

    • Author(s)
      野間 淳
    • Organizer
      第60回代数学シンポジウム
    • Place of Presentation
      静岡大学
    • Year and Date
      2015-09-01
    • Related Report
      2015 Research-status Report
    • Invited

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Published: 2014-04-04   Modified: 2018-03-22  

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