Kyushu University Academic Staff Educational and Research Activities Database
Researcher information (To researchers) Need Help? How to update
Shunsaku Nii Last modified date:2023.05.30

Graduate School
Undergraduate School

 Reseacher Profiling Tool Kyushu University Pure
Academic Degree
Doctor of Science
Country of degree conferring institution (Overseas)
Field of Specialization
Dynamical Systems
Total Priod of education and research career in the foreign country
Outline Activities
Brief description of the research, teaching and direct contribution to the society:

Research:The field of research is dynamical-systemic approach with topological
methods to problems in applied analysis. This topological and
geometric point of view sheds new light on subjects which usually
studied by analytical methods.

Teaching:There are two kinds of courses in terms of the objectives.
Classes in the first category are tought at the faculty of
mathematics in the department of science, and the graduate school
of mathematics. Their aim is to provide discipline for experts of
mathematics. Those in the second one are tought in the department of
engineering in order to offer basic mathematical knowledge and
advanced tools for applications in technology.

Direct contribution to the society:A lecture in the community courses of the
faculty of mathematics in Kyushu University in 2003.
Research Interests
  • Dynamical systems and Stability problem
    keyword : homo/heteroclinic orbit, traveling wave, eigenvalue problem, topological method
  • Studies of topological origins of phase transitions
    keyword : phase transition, topology
Academic Activities
1. Shunsaku Nii, Genericity of interactions with potentials being Morse functions, Journal of Geometry and Physics, 10.1016/j.geomphys.2018.03.013, 129, 233-237, 2018.07, Potential functions defined on a d-dimensional lattice by nearest neighbor coupling are considered. The question is whether the potential functions are Morse functions. It is shown that for generic nearest neighbor couplings the potential functions are Morse functions for any system size..
2. Ayuki Sekisaka, Shunsaku Nii, Computer assisted verification of the eigenvalue problem for one-dimensional Schro ̈dinger operator, Mathematical Challenges to a New Phase of Materials Science, 145-157, 2016.01, 周期的ポテンシャル項を持つシュレーディンガー作用素に指数減衰する摂動を施したものの固有値問題について、Maslov Index のアイディアを用いて計算機援用証明を行った。.
3. Shunsaku Nii, Bifurcations of stationary solutions with triple junctions in phase separation problems --A new view of bifurcation analysis--, Physica D, 238 (2009), pp. 1050-1055, 2009.06.
4. Jian Deng, Shunsaku Nii, An Infinite-dimensional Evans function theory for Elliptic Boundary Value Problems, Journal of Differential Equations , vol. 244 pp. 753--765, 2008.02.
5. Jian Deng, Shunsaku Nii, Infinite-dimensional Evans function theory for elliptic eigenvalue problems in a channel, Journal of Differential Equations, 225 pp.57-89, 2006.06.
Works, Software and Database
1. .
2. .
Educational Activities
Commitments to education:

My teaching duty consists of four kinds of courses:

1.Lectures and exercise courses for freshmen in the faculty of mathematics:
Teaching foundation of mathematical way of thinking, and attitude and the
methods of study to the students who will study mathematics as an academic.

2.Lectures for seniors and graduate students in the faculty of mathematics:
Introducing advanced topics from specific areas in order to provide
good perspectives of the academic to students who finished standard course
of mathematics.

3.Lectures and exercise courses for freshmen and sophomores in the department
of engineering e.t.c.:
Teaching basic knowledge of mathematics such as calculus and liner algebra
to students who will use mathematics as a tool.

4.Lectures for juniors and seniors in the department of engineering:
Providing mathematical tools used in engineering e.t.c. such as differential
equations, Fourier analysis and so on to students who need theses tools.