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2005 Fiscal Year Final Research Report Summary

Study of modulimap of degenerate families of algebraic curves and local signature arizing from automorphic form

Research Project

Project/Area Number 16540036
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field Algebra
Research InstitutionTohoku-Gakuin University

Principal Investigator

ASHIKAGA Tadashi  Tohoku-Gakuin University, Faculty of Engineering, Professor, 工学部, 教授 (90125203)

Co-Investigator(Kenkyū-buntansha) TUCHIHASHI Hiroyasu  Tohoku-Gakuin University, Faculty of General Education, Associated Professor, 教養学部, 助教授 (00146119)
KONNO Kazuhiro  Graduate School of Osaka University, Institute of Science, Professor, 大学院・理学研究科, 教授 (10186869)
Project Period (FY) 2004 – 2005
KeywordsAlgebraic curve / Degenerate family / Signature / Dedekind sum / Stable roduction / Monodromy / Horikawa index / Moduli
Research Abstract

In 2005, we have the following development about the local signature and Horikawa index of degenerate families of algebraic curves :
(1)The case of stable family ; We have already found in 2004 an application of Harris-Mamford formula to maximal-gonal fibration of addgeues. In 2005, We have found a similar application of Eisenbud-Harris formula to even genus case. More precisely, in the case of genus 4, we obtain a formula for local contribution from the Cheu-Konno lower bound But in the case of genus greater than or equal 6, some difficulties remain, because we need more Sharp form of Eisenbud-Harris formula.
(2)The case of unstable family ; We have already describe in 2004 the behavionr of invariants under the stable reduction by using the Dedekind sam of monodromy data In 2005, we have obtained completely explicite formula for there Dedeking sum tern Therefore we can rewrite out previous formula in a simple form so that the induction with respect to the genus in possible. It seems to be interesting from the number theoretic viewpoint.

  • Research Products

    (2 results)

All 2005

All Journal Article (2 results)

  • [Journal Article] Fibered rational surfaces with extremal Mordell-Weil latticies2005

    • Author(s)
      S.Kitagawa, K.Konno
    • Journal Title

      Math. Zeitschrift 251

      Pages: 179-204

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Fibered rational snrfaces with extremal Mordell-Weil lattices2005

    • Author(s)
      S.Kitagawa, K.Konno
    • Journal Title

      Math.Zeitschrift 251

      Pages: 179-204

    • Description
      「研究成果報告書概要(欧文)」より

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Published: 2007-12-13  

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