Project/Area Number  03452003 
Research Category 
GrantinAid for Scientific Research (B).

Research Field 
代数学・幾何学

Research Institution  University of Tokyo 
Principal Investigator 
加藤 和也 東京大学, 理学部, 教授 (90111450)
KAWAMATA Yujiro Univ.of Tokyo,Dept.of Math.Sciences, 大学院数理科学研究科, 教授 (90126037)

CoInvestigator(Kenkyūbuntansha) 
NAKAMURA Hiroaki Univ.of Tokyo,Dept.of Math.Sciences, 大学院数理科学研究科, 助手 (60217883)
NAKAYAMA Noboru Univ.of Tokyo,Dept.of Math.Sciences, 大学院数理科学研究科, 助教授 (10189079)
SAITO Takeshi Univ.of Tokyo,Dept.of Math.Sciences, 大学院数理科学研究科, 助教授 (70201506)
KUROKAWA Nobushige Univ.of Tokyo,Dept.of Math.Sciences, 大学院数理科学研究科, 助教授 (70114866)
SUNADA Toshikazu Univ.of Tokyo,Dept.of Math.Sciences, 大学院数理科学研究科, 教授 (20022741)

Project Fiscal Year 
1991 – 1992

Project Status 
Completed(Fiscal Year 1992)

Budget Amount *help 
¥6,200,000 (Direct Cost : ¥6,200,000)
Fiscal Year 1992 : ¥2,800,000 (Direct Cost : ¥2,800,000)
Fiscal Year 1991 : ¥3,400,000 (Direct Cost : ¥3,400,000)

Keywords  algebraic varieties / number theory / semistable reduction / minimal model / zeta function / log rithmic structure / Hecke character / Galois representation / 代数多様体 / 整数論 / 半安定退化 / 極小モデル / ゼータ関数 / 対数構造 / ヘッケ指標 / ガロア表現 / 数論的代数幾何 / ゼタ関数 / P進Hodge理論 / 岩沢理論 / 形式群 / 局所定数 / 基本群 
Research Abstract 
The purpose of this research was to investigate the number theory of algebraic varieties defined over a ring of algebraic integers. In order to start this investigation, it is important to replace the originalvariety by a more natural model by a birational transformation. If the given variety has relative dimension 1 over the ring of integers, then the classical minimal model theory provides us the canonical model. Kawamata tried to extend the minimal model theory to higher dimensional case, and succeeded in the case in which the relative dimension is 2 and the variety has semistable reduction. In the course of the proof, newly developed theory of algebraic 3folds over the complex numbers was used. The difficulty in the proof came from the fact that the vanishing theorem of Kodaira type, which was very useful in the case over the complex numbers, is false in positive characteristic. The singular fiber of a variety with semistable reduction is a normal crossing variety. Conversely, Kawam
… More
ata considered the smoothing of normal crossing variety into a variety with semistable reduction, and developed the theory of logarithmic deformations with Yoshinori Namikawa at Sophia University. In particular, they proved the existence of a smoothing of a degenerate CalabiYau variety. The cohomology theory is an important tool in the investigaition of algebraic varieties. Saito investigated the 1 dimensional Galois representations on the determinant of Ladic cohomology groups. In the case of constant coefficients, he obtained the description of the corresponding quadratic extensions. In the case of variable coefficients, he proved that they are described by the algebraic Hecke characters determined by the Jacobi sums. The zeta functions an analytic object which is attached to an algebraic variety over the ring of integers. There are several mysterious conjectures connecting the zeta functions and the number theory of algebraic varieties. Kurokawa investigated multiple zeta funcitons and multiple trigonometric functions, and found formulas of the Gamma factor of the Selberg zeta functions and of the special values of the zeta functions. Less
