I was a Global COE PD at Department of Mathematics at Kyoto University.
2000, Faculty of Science, Kyoto University
2004, Department of Mathematics at Kyoto University
2009/4-2013/3, GCOE-PD at Department of Mathematics at Kyoto University
2010/10-2012/3, Part-time teacher at Kyoto University(Additional)
2012/8- Part-time teacher at CJLC of Osaka University(Additional)
2013/4-, Part-time teacher at Kyoto Kyoiku University(Additional)
2020/4-, Part-time teacher at Kobe University(Additional)
e-mail: y64k at chive.ocn.ne.jp (at should be replaced by @) (4/28/2021) I cannot receive e-mails to this e-mail address until 5/7/2021.
twitter: https://twitter.com/tyamada1093
I am interested in easily stated problems in number theory and discrete mathematics. Many of such problems are formulated and discussed by elementary number theory, analytic number theory, combinatorics, graph theory, computability theory and others.
At present, my research interest lies in properties of values of classical arithmetic functions related to divisors of integers, such as σ and φ.
(5/30) Digest / 1Q, 7th (Japanese) tex pdf
(5/23) Digest / 1Q, 6th (Japanese) tex pdf Supplement on 5th and 6th classes (Japanese) tex pdf
(5/9) Digest / 1Q, 4th (Japanese) tex pdf Report problems tex pdf
(4/18) Digest / 1Q, 2nd (Japanese) tex pdf
(4/11) Digest / 1Q, 1st (Japanese) tex pdf Supplement on completeness of real numbers (Japanese) tex pdf
(6/7) Exam problems / 1Q, 7th (in Japanese) tex pdf Answers (in Japanese) tex pdf
(5/21) Report problems / 1Q, 5th (in Japanese) tex pdf
(6/7) Exam problems / 1Q, 7th (in Japanese) tex pdf Answers (in Japanese) tex pdf
(5/21) Report problems / 1Q, 5th (in Japanese) tex pdf
(5/21) Addendum / 1Q, 2th (in Japanese) tex pdf
(2/2) Digest and Exercises / 3Q, 8th (in Japanese) tex pdf
(1/26) Digest and Exercises / 3Q, 7th (in Japanese) tex pdf Answers to exercises in 7th (in Japanese) tex pdf
(1/19) Digest and Exercises / 3Q, 6th (in Japanese) tex pdf Answers to exercises in 6th (in Japanese) tex pdf Supplement (in Japanese) tex pdf
(1/12) Digest and Exercises / 3Q, 5th (in Japanese) tex pdf Answers to exercises in 4th-5th (in Japanese) tex pdf
(12/22) Digest and Exercises / 3Q, 4th (in Japanese) tex pdf, revised ver. tex pdf Supplement (in Japanese) zip (source) pdf
(12/15) Digest and Exercises / 3Q, 3rd (in Japanese) tex pdf Answers to exercises in 3th (in Japanese) tex pdf
(12/8) Digest and Exercises / 3Q, 2nd (in Japanese) tex pdf Answers to exercises in 2nd (in Japanese) tex pdf
(12/1) Digest and Exercises / 3Q, 1st (in Japanese) tex pdf Supplement (in Japanese) tex pdf Answers to exercises in 1st (in Japanese) tex pdf
(11/19) Digest and Exercises / 3Q, 7th (in Japanese) tex pdf Answers to exercises in 7th (in Japanese) tex pdf
(11/12) Digest and Exercises / 3Q, 6th (in Japanese) tex pdf Answers to exercises in 6th (in Japanese) tex pdf
(11/10) Digest and Exercises / 3Q, 5th (in Japanese) tex pdf Answers to exercises in 5th (in Japanese) tex pdf
(10/27) Digest and Exercises / 3Q, 4th (in Japanese) tex pdf Answers to exercises in 3rd-4th (in Japanese) tex pdf
(10/20) Digest and Exercises / 3Q, 3rd (in Japanese) tex pdf
(10/13) Digest and Exercises / 3Q, 2nd (in Japanese) tex pdf Answers to exercises in 1st-2nd (in Japanese) tex pdf
(10/6) Digest and Exercises / 3Q, 1st (in Japanese) tex pdf
(8/11) Digest and Exercises / 2Q, 7th (in Japanese) tex pdf
(8/4) Digest and Exercises / 2Q, 6th (in Japanese) tex pdf
(7/28) Digest and Exercises / 2Q, 5th (in Japanese) tex pdf
(7/21) Digest and Exercises / 2Q, 4th (in Japanese) tex pdf
(7/14) Digest and Exercises / 2Q, 3rd (in Japanese) tex pdf
(7/7) Digest and Exercises / 2Q, 2nd (in Japanese) tex pdf
(6/30) Digest and Exercises / 2Q, 1st (in Japanese) tex pdf
(6/23) Digest and Exercises / 1Q, 7th (in Japanese) tex pdf (7/20/2020 added) Answers to the 7th exercises tex pdf
(6/16) Digest and Exercises / 1Q, 6th (in Japanese) tex pdf
(6/9) Digest and Exercises / 1Q, 5th (in Japanese) tex pdf
(6/2) Digest and Exercises / 1Q, 4th (in Japanese) tex pdf
(5/27) Digest and Exercises / 1Q, 3rd (in Japanese) tex pdf
(5/20) Digest and Exercises / 1Q, 2nd (in Japanese) tex pdf
(5/13) Digest and Exercises / 1Q, 1st (in Japanese) tex pdf
(8/11) Digest and Exercises / 2Q, 7th (in Japanese) tex pdf
(8/4) Digest and Exercises / 2Q, 6th (in Japanese) tex pdf
(7/28) Digest and Exercises / 2Q, 5th (in Japanese) tex pdf
(7/21) Digest and Exercises / 2Q, 4th (in Japanese) tex pdf
(7/14) Digest and Exercises / 2Q, 3rd (in Japanese) tex pdf
(7/7) Digest and Exercises / 2Q, 2nd (in Japanese) tex pdf
(6/30) Digest and Exercises / 2Q, 1st (in Japanese) tex pdf
(6/23) Digest and Exercises / 1Q, 7th (in Japanese) tex pdf (7/18/2020 added) Answers to the 7th exercises tex pdf
(6/16) Digest and Exercises / 1Q, 7th (in Japanese) tex pdf
(6/9) Digest and Exercises / 1Q, 7th (in Japanese) tex pdf
(6/2) Digest and Exercises / 1Q, 7th (in Japanese) tex pdf
(5/27) Digest and Exercises / 1Q, 7th (in Japanese) tex pdf
(5/20) Digest and Exercises / 1Q, 7th (in Japanese) tex pdf
(5/13) Digest and Exercises / 1Q, 7th (in Japanese) tex pdf
(7/25) Report Problems tex (in Japanese) pdf (in Japanese)
(6/17) Report Problems tex (in Japanese) pdf (in Japanese)
(8/1) Extra exercises tex (in Japanese) pdf (in Japanese) (8/4 revised) tex (in Japanese) pdf (in Japanese) Figures (zip)
(7/28) Term-End Report Problems tex (in Japanese) pdf (in Japanese)
(6/17) Report Problems tex (in Japanese) pdf (in Japanese)
(7/28) Linear mappings between vector spaces tex (in Japanese) pdf (in Japanese)
(7/17) Term-End Report Problems tex (in Japanese) pdf (in Japanese)
(7/17) Sums and intersections of vector spaces tex (in Japanese) pdf (in Japanese)
(6/30) Vector spaces tex (in Japanese) pdf (in Japanese) (Addendum) tex (in Japanese) pdf (in Japanese)
(6/6) Report Problems tex (in Japanese) pdf (in Japanese)
(6/5) Linear transformations in plane and space tex (in Japanese) pdf (in Japanese)
(5/29) Vectors in plane and space tex (in Japanese) pdf (in Japanese)
(8/20) Outline of answers of the examination problems tex (in Japanese) pdf (in Japanese)
(1/18) Calculation of fractions tex (in Japanese) pdf (in Japanese)
See old lecture notes for calculation of natural numbers.
(7/29) The 5-6th lectures tex (in Japanese) pdf (in Japanese)
(7/29) The 4-5th lectures tex (in Japanese) pdf (in Japanese)
(7/22) The third-4th lectures tex (in Japanese) pdf (in Japanese)
(5/27) The second-third lectures tex (in Japanese) pdf (in Japanese)
(5/13) The first-second lectures tex (Unicode, in Japanese) pdf (in Japanese)
(5/7) The first lecture tex (Unicode, in Japanese) pdf (in Japanese)
(5/20) The second-third lecture tex (in Japanese) pdf
The examination was held in July 29. It mainly concerns to convergence and limit of sequences and differentiation of functions.
Here is the homework given in Jul 8, Deadline Apr 5. It concerns to differentiation, integration and convergence of series.
It is not obligatory.
Here is the homework given in May 20, Deadline July 1. It mainly concerns to convergence of real sequences.
It is not obligatory.
The examination was held in January 26. It mainly concerns to linear mappings between vector spaces, the method of least squares and the eigenvalue problem.
A quiz was held in December 8. It mainly concerns to linear independence of vectors.
Proofs of the infinitude of primes (dvi)(1/12/2010, 8/7/2014, 11/12/2018 revised) (pdf) (8/7/2014 pdf updated TeX source(1/12/2010, 8/7/2014, 11/12/2018 revised)
Proofs of the fundamental theorem of arithmetic (dvi) (7/1/2015)(6/4/2019 revised) Proofs of the fundamental theorem of arithmetic (pdf) (7/1/2015)(6/4/2019 revised) TeX source (7/1/2015)(6/4/2019 revised)
An exponential diophantine equation related to odd perfect numbers (at Diophantine Analysis and Related Fields 2018) pdf (3/4/2018) source (3/4/2018)
Three-term Machin-type formulae (at RIMS Workshop 2018 "Analytic Number Theory and Related Topics" , 10/29/2018) (11/12/2018) (pdf) source (zip) (6/29/2020 added) See also the above preprint and revision list.
Almost Lehmer numbers (at RIMS Workshop 2020 "Problems and Prospects in Analytic Number Theory" , 11/27/2020) (12/7/2020, with revision) (pdf) source (zip) (4/28/2021 added) See also the above paper.
The Mathematical Society of Japan
(2017/4/6 added)The On-Line Encyclopedia of Integer Sequences (OEIS)