Project/Area Number  10640139 
Research Category 
GrantinAid for Scientific Research (C).

Section  一般 
Research Field 
General mathematics (including Probability theory/Statistical mathematics)

Research Institution  Meijo University 
Principal Investigator 
HARAMIMACHI Yuko Meijo University, Faculty of Science and Technology, Lecturer, 理工学部, 講師 (00218629)

CoInvestigator(Kenkyūbuntansha) 
SAITO Kimiaki Meijo University, Faculty of Science and Technology, Assistant Professor, 理工学部, 助教授 (90195983)
KUBOTA Tomio Meijo University, Faculty of Science and Technology, Professor, 理工学部, 教授 (40022511)

Project Fiscal Year 
1998 – 1999

Project Status 
Completed(Fiscal Year 1999)

Budget Amount *help 
¥1,000,000 (Direct Cost : ¥1,000,000)
Fiscal Year 1999 : ¥500,000 (Direct Cost : ¥500,000)
Fiscal Year 1998 : ¥500,000 (Direct Cost : ¥500,000)

Keywords  ergadic theory / Diophantine approsimation / Simultaneous approximation / エルゴード理論 / ディオファンタス近似 / 同時近似 
Research Abstract 
In Diophantine approximation theory, we consider a conjective of Littlewood, that is, the simultaneous approximation problem for any n(n【greater than or equal】2) real numbers. It is known that this conjecture is true for n = 2. The purpose of this research is to discuss about this conjecture for two quadratic irrationals. In 1998, we tried to approach by the method of H.Dickinson(1993,1994). This method is to combine a Diophantine inequality for the simultaneous or not simultaneous linear forms with the natural extension, skew product and substitution in ergodic theory. But it was failed. In 1999, we tried to approach by using an analogue of the inequality of Littlewood conjecture, based on the Minkowski's convex body theorem. This inequality was shown by Minkowski and W, M..Schmidt, and improved by Cassels, Davenport and Mahler. By using This result and the periodicity of the expansions of two quadratic irrasionals, we may improve the inequality.
