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Cohomology of algebraic varieties and Galois representations

Research Project

Project/Area Number 22244001
Research Category

Grant-in-Aid for Scientific Research (A)

Allocation TypeSingle-year Grants
Section一般
Research Field Algebra
Research InstitutionThe University of Tokyo

Principal Investigator

SAITO Takeshi  東京大学, 数理(科)学研究科(研究院), 教授 (70201506)

Co-Investigator(Kenkyū-buntansha) TAMAGAWA Akio  京都大学, 数理解析研究所, 教授 (00243105)
Co-Investigator(Renkei-kenkyūsha) TAGUCHI Yuichiro  九州大学, 数理学研究院, 准教授 (90231399)
TSUZUKI Nobuo  東北大学, 理学研究科, 教授 (10253048)
TSUJI Takeshi  東京大学, 大学院数理科学研究科, 教授 (40252530)
Project Period (FY) 2010-04-01 – 2014-03-31
Project Status Completed (Fiscal Year 2013)
Budget Amount *help
¥19,370,000 (Direct Cost: ¥14,900,000、Indirect Cost: ¥4,470,000)
Fiscal Year 2013: ¥3,640,000 (Direct Cost: ¥2,800,000、Indirect Cost: ¥840,000)
Fiscal Year 2012: ¥6,890,000 (Direct Cost: ¥5,300,000、Indirect Cost: ¥1,590,000)
Fiscal Year 2011: ¥3,640,000 (Direct Cost: ¥2,800,000、Indirect Cost: ¥840,000)
Fiscal Year 2010: ¥5,200,000 (Direct Cost: ¥4,000,000、Indirect Cost: ¥1,200,000)
Keywords数論幾何学 / 分岐理論 / l進層 / 特性サイクル / ガロワ表現 / 代数学 / 整数論 / 代数幾何 / 代数多様体 / 分岐 / 特性輪体 / 隣接輪体 / 非輪状性 / ガロワ被覆 / 余接束 / エタール・コホモロジー / 超曲面 / 判別式 / 導手 / 局所体 / Stiefel-Whitney類 / 直交表現
Research Abstract

I find that non-logarithmic version is geometrically more important than the logarithmic one in ramification theory. I constructed the non-logarithmic theory of the characteristic cycle of an l-adic sheaf in codimension at most 1. Using the method of cutting by curves and established acyclicity of morphisms of varieties.
For a sheaf on a surface, I defined the characteristic cycle everywhere on the surface and proved a formula for the Euler number and an analog of the Milnor formula on vanishing cycles. Though limited to surfaces, this is a significant result achieving the aim to construct a theory of characteristic cycles in higher dimension.
I also studied the determinant and the second Stiefel-Whitney class of the Galois representation defined by l-adic cohomology of a variety of even dimension.

Report

(5 results)
  • 2013 Annual Research Report   Final Research Report ( PDF )
  • 2012 Annual Research Report
  • 2011 Annual Research Report
  • 2010 Annual Research Report
  • Research Products

    (58 results)

All 2014 2013 2012 2011 2010 Other

All Journal Article (13 results) (of which Peer Reviewed: 7 results) Presentation (43 results) (of which Invited: 9 results) Remarks (2 results)

  • [Journal Article] Ramification theory for varieties over a local field2013

    • Author(s)
      Kazuya Kato, Takeshi Saito
    • Journal Title

      Publ. Math. IHES.

      Volume: 117 Issue: 1 Pages: 1-178

    • DOI

      10.1007/s10240-013-0048-z

    • Related Report
      2013 Final Research Report 2012 Annual Research Report
  • [Journal Article] The second Stiefel-Whitney classes of l-adic cohomology2013

    • Author(s)
      Takeshi Saito
    • Journal Title

      J. fur die reine und angewandte Math.

      Volume: Issue 681 Issue: 681 Pages: 101-147

    • DOI

      10.1515/crelle-2012-0035

    • Related Report
      2013 Final Research Report 2012 Annual Research Report
  • [Journal Article] A uniform open image theorem for l-adic representations II2013

    • Author(s)
      Anna Cadoret and Akio Tamagawa
    • Journal Title

      Duke Math. J.

      Volume: 162 Issue: 12 Pages: 2301-2344

    • DOI

      10.1215/00127094-2323013

    • Related Report
      2013 Annual Research Report 2013 Final Research Report
    • Peer Reviewed
  • [Journal Article] The determinant and the discriminant of a hypersurface of even dimension2012

    • Author(s)
      Takeshi Saito
    • Journal Title

      Math. Research Letters

      Volume: 19 Issue: 4 Pages: 855-871

    • DOI

      10.4310/mrl.2012.v19.n4.a10

    • Related Report
      2013 Final Research Report 2012 Annual Research Report
  • [Journal Article] Ramification of local fields with imperfect residue fields III2012

    • Author(s)
      T. Saito
    • Journal Title

      Mathematische Annalen

      Volume: 352 Issue: 3 Pages: 567-580

    • DOI

      10.1007/s00208-011-0652-5

    • Related Report
      2013 Final Research Report 2012 Annual Research Report 2011 Annual Research Report
    • Peer Reviewed
  • [Journal Article] Uniform boundedness of p-primary torsion of abelian schemes2012

    • Author(s)
      Anna Cadoret and Akio Tamagawa
    • Journal Title

      Inv. Math.

      Volume: 2011;188, no.1 Issue: 1 Pages: 83-125

    • DOI

      10.1007/s00222-011-0343-6

    • Related Report
      2013 Final Research Report 2011 Annual Research Report
    • Peer Reviewed
  • [Journal Article] RAMIFICATION AND CLEANLINESS2011

    • Author(s)
      Ahmed Abbes, Takeshi Saito
    • Journal Title

      Tohoku Mathematical Journal, Second Series

      Volume: 63 Issue: 4 Pages: 775-853

    • DOI

      10.2748/tmj/1325886290

    • NAID

      110008764870

    • ISSN
      0040-8735, 2186-585X
    • Related Report
      2013 Final Research Report 2011 Annual Research Report
  • [Journal Article] On the Hom-form of Grothendieck's birational anabelian conjecture in characteristic p>02011

    • Author(s)
      Mohamed Saidi and Akio Tamagawa
    • Journal Title

      Algebra and Number Theory 5

      Volume: no.2 Pages: 131-184

    • Related Report
      2013 Final Research Report
  • [Journal Article] On a weak variant of the geometric torsion conjecture2011

    • Author(s)
      Anna Cadoret and Akio Tamagawa
    • Journal Title

      Journal of Algebra

      Volume: 346, no.1 Pages: 227-247

    • Related Report
      2013 Final Research Report
  • [Journal Article] On the Hom-form of Grothendieck's birational anabelian conjecture in characteristic p>02011

    • Author(s)
      Mohamed Saidi, Akio Tamagawa
    • Journal Title

      Algebra and Number Theory

      Volume: 5 Issue: 2 Pages: 131-184

    • DOI

      10.2140/ant.2011.5.131

    • Related Report
      2011 Annual Research Report
    • Peer Reviewed
  • [Journal Article] Ramification of local fields with imperfect residue fields III2011

    • Author(s)
      Takeshi Saito
    • Journal Title

      Mathematische Annalen

      Volume: 電子速報版

    • Related Report
      2010 Annual Research Report
    • Peer Reviewed
  • [Journal Article] Local Fourier transform and epsilon factors2010

    • Author(s)
      Ahmed Abbes, Takeshi Saito
    • Journal Title

      Compositio Mathematica

      Volume: 146-6 Pages: 1507-1551

    • Related Report
      2010 Annual Research Report
    • Peer Reviewed
  • [Journal Article] On the Hom-form of Grothendieck's birational anabelian conjecture incharacteristic p>0

    • Author(s)
      Mohamed Saidi, Akio Tamagawa
    • Journal Title

      Algebra and Number Theory

    • Related Report
      2010 Annual Research Report
    • Peer Reviewed
  • [Presentation] Characteristic cycles of a constructible sheaf on a surface2014

    • Author(s)
      Takeshi Saito
    • Organizer
      Geometry & Arithmetic of Surfaces
    • Place of Presentation
      LMU & TU Munich
    • Year and Date
      2014-03-18
    • Related Report
      2013 Final Research Report
  • [Presentation] Characteristic cycles of a constructible sheaf on a surface2014

    • Author(s)
      Takeshi Saito
    • Organizer
      Conference on Motives and Galois groups on the occasion of Uwe Jannsen's 60th birthday
    • Place of Presentation
      University of Regensburg
    • Year and Date
      2014-03-12
    • Related Report
      2013 Final Research Report
  • [Presentation] Characteristic cycles of a constructible sheaf on a surface2014

    • Author(s)
      Takeshi Saito
    • Organizer
      Arithmetic and Algebraic Geometry 2014
    • Place of Presentation
      東大数理
    • Year and Date
      2014-01-29
    • Related Report
      2013 Final Research Report
  • [Presentation] Wild Ramification and the Cotangent Bundle2013

    • Author(s)
      Takeshi Saito
    • Organizer
      AMC 2013
    • Place of Presentation
      Busan
    • Year and Date
      2013-07-03
    • Related Report
      2013 Final Research Report
  • [Presentation] The second Stiefel-Whitney class of l-adic cohomology2012

    • Author(s)
      Takeshi Saito
    • Organizer
      Galois Representations and Arithmetic Geometry
    • Place of Presentation
      Institut de Mathematiques de Bordeaux
    • Year and Date
      2012-07-11
    • Related Report
      2013 Final Research Report
  • [Presentation] Discriminant and determinant of a hypersurface of even dimension2012

    • Author(s)
      Takeshi Saito
    • Organizer
      Arithmetic and Algebraic Geometry 2012
    • Place of Presentation
      Univ. of Tokyo
    • Year and Date
      2012-02-17
    • Related Report
      2013 Final Research Report
  • [Presentation] Discriminant and determinant of a hypersurface of even dimension2012

    • Author(s)
      Takeshi Saito
    • Organizer
      Arithmetic and Algebraic Geometry 2012
    • Place of Presentation
      東京大学数理科学研究科(招待講演)
    • Year and Date
      2012-02-17
    • Related Report
      2011 Annual Research Report
  • [Presentation] Introduction to wild ramification of schemes and sheaves2012

    • Author(s)
      Takeshi Saito
    • Organizer
      Arizona Winter School 2012 : Ramification and Geometry
    • Place of Presentation
      University of Arizona in Tucson
    • Related Report
      2013 Final Research Report
  • [Presentation] Discriminant and determinant of a hypersurface of even dimension2011

    • Author(s)
      Takeshi Saito
    • Organizer
      Japan-Taiwan Mini workshop on Arithmetic Algebraic Geometry and related topics
    • Place of Presentation
      Inst.of Mathematics, Academia Sinica(台湾)(招待講演)
    • Year and Date
      2011-11-18
    • Related Report
      2011 Annual Research Report
  • [Presentation] Discriminant and the determinant of a complete intersection2011

    • Author(s)
      Takeshi Saito
    • Organizer
      Workshop on arithmetic geometry 2011
    • Place of Presentation
      Okinawa Shogaku, 10:00-11:20
    • Year and Date
      2011-10-10
    • Related Report
      2013 Final Research Report
  • [Presentation] Discriminant and determinant of a complete intersection of even dimension2011

    • Author(s)
      Takeshi Saito
    • Organizer
      Workshop on arithmetic geometry 2011
    • Place of Presentation
      沖縄尚学高校(招待講演)
    • Year and Date
      2011-10-10
    • Related Report
      2011 Annual Research Report
  • [Presentation] Second Stiefel-Whitney class of l-adic cohomology2011

    • Author(s)
      Takeshi Saito
    • Organizer
      Geometrie Arithmetique et motivique, CIRM
    • Year and Date
      2011-09-19
    • Related Report
      2013 Final Research Report
  • [Presentation] Second Stiefel-Whitney class of 1-adic cohomology2011

    • Author(s)
      Takeshi Saito
    • Organizer
      Geometrie Arithmetique et motivique
    • Place of Presentation
      CIRM(フランス)(招待講演)
    • Year and Date
      2011-09-19
    • Related Report
      2011 Annual Research Report
  • [Presentation] Discriminant and determinant of a hypersurface of even dimension (joint work with J-P. Serre)2011

    • Author(s)
      Takeshi Saito
    • Organizer
      Une apres-midi de Geometrie Arithmetique a l'IHES
    • Year and Date
      2011-09-12
    • Related Report
      2013 Final Research Report
  • [Presentation] Discriminant and determinant of a hypersurface of even dimension2011

    • Author(s)
      Takeshi Saito
    • Organizer
      Une apres-midi de Geometrie Arithmetique
    • Place of Presentation
      IHES(フランス)(招待講演)
    • Year and Date
      2011-09-12
    • Related Report
      2011 Annual Research Report
  • [Presentation] 偶数次元の超曲面の判別式と行列式2011

    • Author(s)
      斎藤毅
    • Organizer
      仙台シンポジウム
    • Place of Presentation
      東北大学情報科学研究科(招待講演)
    • Year and Date
      2011-08-02
    • Related Report
      2011 Annual Research Report
  • [Presentation] Wild ramification of schemes and sheaves2011

    • Author(s)
      Takeshi Saito
    • Organizer
      Arithmetic and Algebraic Geometry
    • Related Report
      2013 Final Research Report
  • [Presentation] Discriminant and determinant of a hypersurface of even dimension (joint work with J-P. Serre)2011

    • Author(s)
      Takeshi Saito
    • Organizer
      2011 Japan-Taiwan Mini workshop on Arithmetic Algebraic Geometry and related topics
    • Related Report
      2013 Final Research Report
  • [Presentation] l-進 Riemann-Roch公式 (加藤和也氏との共同研究)2010

    • Author(s)
      斎藤毅
    • Organizer
      代数的整数論とその周辺
    • Place of Presentation
      京都大学数理解析研究所
    • Year and Date
      2010-12-06
    • Related Report
      2013 Final Research Report
  • [Presentation] 1-進 Riemann-Roch 公式(加藤和也氏との共同研究)2010

    • Author(s)
      斎藤毅
    • Organizer
      代数的整数論とその周辺
    • Place of Presentation
      京都大学数理解析研究所
    • Year and Date
      2010-12-06
    • Related Report
      2010 Annual Research Report
  • [Presentation] Wild ramification of schemes and sheaves2010

    • Author(s)
      Takeshi Saito
    • Organizer
      Witt vectors, foliations, and absolute de Rhamcohomology
    • Place of Presentation
      名古屋大学多元数理研究科
    • Year and Date
      2010-11-24
    • Related Report
      2013 Final Research Report
  • [Presentation] Wild ramification of schemes and sheaves2010

    • Author(s)
      Takeshi Saito
    • Organizer
      Witt vectors, foliations, and absolute de Rham cohomology
    • Place of Presentation
      名古屋大学多元数理研究科
    • Year and Date
      2010-11-24
    • Related Report
      2010 Annual Research Report
  • [Presentation] Wild ramification of schemes and sheaves2010

    • Author(s)
      Takeshi Saito
    • Organizer
      Pan Asian Numberheory Conference
    • Place of Presentation
      京都大学数理解析研究所
    • Year and Date
      2010-09-17
    • Related Report
      2013 Final Research Report
  • [Presentation] Wild ramification of schemes and sheaves2010

    • Author(s)
      Takeshi Saito
    • Organizer
      Pan Asian Number Theory Conference
    • Place of Presentation
      京都大学数理解析研究所
    • Year and Date
      2010-09-17
    • Related Report
      2010 Annual Research Report
  • [Presentation] Representations of etale fundamental groups and applications (joint work with Anna Cadoret)2010

    • Author(s)
      Akio Tamagawa
    • Organizer
      Pan Asian Number Theory Conference
    • Place of Presentation
      京都大学数理解析研究所
    • Year and Date
      2010-09-13
    • Related Report
      2013 Final Research Report
  • [Presentation] Representations of etale fundamental groups and applications(joint work with Anna Cadoret)2010

    • Author(s)
      Akio Tamagawa
    • Organizer
      Pan Asian Number Theory Conference
    • Place of Presentation
      京都大学数理解析研究所
    • Year and Date
      2010-09-13
    • Related Report
      2010 Annual Research Report
  • [Presentation] Wild ramification of schemes and sheaves2010

    • Author(s)
      Takeshi Saito
    • Organizer
      国際数学者会議
    • Place of Presentation
      ハイデラバード(インド)
    • Year and Date
      2010-08-27
    • Related Report
      2013 Final Research Report
  • [Presentation] Wild ramification of schemes and sheaves2010

    • Author(s)
      Takeshi Saito
    • Organizer
      国際数学者会議
    • Place of Presentation
      インド・ハイデラバード
    • Year and Date
      2010-08-27
    • Related Report
      2010 Annual Research Report
  • [Presentation] Hasse-Arf theorem in higher dimension2010

    • Author(s)
      Takeshi Saito
    • Organizer
      Galois representations in arithmetic and geometry
    • Place of Presentation
      ゴア(インド)
    • Year and Date
      2010-08-11
    • Related Report
      2013 Final Research Report
  • [Presentation] Hasse-Arf theorem in higher dimension2010

    • Author(s)
      Takeshi Saito
    • Organizer
      Galois representations in arithmetic and geometry
    • Place of Presentation
      インド・ゴア
    • Year and Date
      2010-08-11
    • Related Report
      2010 Annual Research Report
  • [Presentation] An l-adic Riemann-Roch formula (joint work with Kazuya Kato)2010

    • Author(s)
      Takeshi Saito
    • Organizer
      Regulators,III
    • Place of Presentation
      バルセロナ(スペイン)
    • Year and Date
      2010-07-20
    • Related Report
      2013 Final Research Report
  • [Presentation] An 1-adic Riemann-Roch formula(joint work with Kazuya Kato)2010

    • Author(s)
      Takeshi Saito
    • Organizer
      Regulators, III
    • Place of Presentation
      スペイン・バルセロナ
    • Year and Date
      2010-07-20
    • Related Report
      2010 Annual Research Report
  • [Presentation] 偶数次元の超曲面の判別式と行列式

    • Author(s)
      斎藤毅
    • Organizer
      仙台シンポジウム
    • Related Report
      2013 Final Research Report
  • [Presentation] Wild Ramification and the Cotangent Bundle

    • Author(s)
      Takeshi Saito
    • Organizer
      PANT (Pan Asia Number Theory) conference, VIASM
    • Related Report
      2013 Final Research Report
  • [Presentation] Wild Ramification and the Cotangent Bundle

    • Author(s)
      Takeshi Saito
    • Organizer
      AMC 2013
    • Place of Presentation
      Busan Bexco (韓国)
    • Related Report
      2013 Annual Research Report
    • Invited
  • [Presentation] Wild Ramification and the Cotangent Bundle

    • Author(s)
      Takeshi Saito
    • Organizer
      PANT (Pan Asia Number Theory) conference,
    • Place of Presentation
      VIASM ハノイ (ベトナム)
    • Related Report
      2013 Annual Research Report
    • Invited
  • [Presentation] l 進層の分岐と特性多様体

    • Author(s)
      斎藤 毅
    • Organizer
      第三回九州合同セミナー
    • Place of Presentation
      佐賀大学
    • Related Report
      2013 Annual Research Report
    • Invited
  • [Presentation] Characteristic cycles of a constructible sheaf on a surface

    • Author(s)
      Takeshi Saito
    • Organizer
      Arithmetic and Algebraic Geometry 2014
    • Place of Presentation
      東京大学大学院数理科学研究科
    • Related Report
      2013 Annual Research Report
    • Invited
  • [Presentation] Characteristic cycles of a constructible sheaf on a surface

    • Author(s)
      Takeshi Saito
    • Organizer
      Conference on Motives and Galois groups on the occasion of Uwe Jannsen's 60th birthday
    • Place of Presentation
      レーゲンスブルク大学 (ドイツ)
    • Related Report
      2013 Annual Research Report
    • Invited
  • [Presentation] Characteristic cycles of a constructible sheaf on a surface

    • Author(s)
      Takeshi Saito
    • Organizer
      Geometry & Arithmetic of Surfaces
    • Place of Presentation
      LMU ミュンヘン (ドイツ)
    • Related Report
      2013 Annual Research Report
    • Invited
  • [Presentation] The second Stiefel-Whitney class of l-adic cohomology

    • Author(s)
      斎藤 毅
    • Organizer
      Galois Representations and Arithmetic Geometry
    • Place of Presentation
      ボルドー大学
    • Related Report
      2012 Annual Research Report
    • Invited
  • [Presentation] Wild Ramification and the Cotangent Bundle

    • Author(s)
      斎藤 毅
    • Organizer
      Asian Mathematicl Conference 2013
    • Place of Presentation
      Bexco プサン
    • Related Report
      2012 Annual Research Report
    • Invited
  • [Presentation] The monodromy weight conjecture and perfectoid spaces (after Peter Scholze)

    • Author(s)
      斎藤 毅
    • Organizer
      Vietnam Institute of Advanced Studies in Mathematics Annual Meeting 2013
    • Place of Presentation
      VIASM ハノイ
    • Related Report
      2012 Annual Research Report
    • Invited
  • [Remarks] 斎藤毅 ホームページ

    • URL

      http://www.ms.u-tokyo.ac.jp/~t-saito/

    • Related Report
      2012 Annual Research Report
  • [Remarks] 東京数論幾何週間 ホームページ

    • URL

      http://www.ms.u-tokyo.ac.jp/~t-saito/conf/agwtodai/agwtodai.html

    • Related Report
      2012 Annual Research Report

URL: 

Published: 2010-08-23   Modified: 2019-07-29  

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