Ibaraki University's
College of Education
Teacher Training Course (Mathematics Education)


UMEZU kenichiro


  1. 筑波大学数学系準研究員(文部技官) 1993/06/16-1997/02/28
  2. 筑波大学数学系助手 1997/03/01-1997/03/31
  3. 前橋工科大学工学部講師 1997/04/01-2001/03/31
  4. 前橋工科大学工学部助教授 2001/04/01-2007/03/31
  5. 前橋工科大学工学部准教授 2007/04/01-2008/03/31
  6. 茨城大学教育学部准教授 2008/04/01-2012/03/31
  7. 茨城大学教育学部教授 2012/04/01-Present

Academic background

  1. University of Tsukuba First Cluster of College College of Natural Sciences 1988/03 Graduated
  2. University of Tsukuba Graduate School, Division of Mathematics Doctor course 1993/03 Completed

Academic degrees

  1. Doctor of Mathematics University of Tsukuba 1993/03

Research Areas

  1. Basic Analysis

Research keywords

  1. 非線形楕円型境界値問題,非線型境界条件,concave-convex 非線形性,変分法,固有値問題,符号不定係数,分岐理論,写像度,位相的手法,人口動態論.

Subject of research

  1. 半線形楕円型境界値問題の正値解集合の構造について 1995-Present


  1. Research paper (scientific journal) Joint Positive solutions of an elliptic Neumann problem with a sublinear indefinite nonlinearity Uriel Kaufmann, Humberto Ramos Quoirin, Kenichiro Umezu Nonlinear Differential Equations and Applications NoDEA 25:12/ online published 2018 10.1007/s00030-018-0502-1
  2. Research paper (scientific journal) Joint A loop type component in the non-negative solutions set of an indefinite elliptic problem Humberto Ramos Quoirin, Kenichiro Umezu Communications on Pure and Applied Analysis 17/ 3, 1255-1269 2018 10.3934/cpaa.2018060
  3. Research paper (scientific journal) Joint Positivity results for indefinite sublinear elliptic problems via a continuity argument Uriel Kaufmann, Humberto Ramos Quoirin, Kenichiro Umezu Journal of Differential Equations 263/ 8, 4481-4502 2017 10.1016/j.jde.2017.05.021
  4. Research paper (scientific journal) Joint An indefinite concave-convex equation under a Neumann boundary condition II Humberto Ramos Quoirin, Kenichiro Umezu Topological Methods in Nonlinear Analysis 49/ 2, 739-756 2017 10.12775/TMNA.2017.007
  5. Research paper (scientific journal) Joint An indefinite concave-convex equation under a Neumann boundary condition I Humberto Ramos Quoirin, Kenichiro Umezu Israel Journal of Mathematics 220/ 1, 103-160 2017 10.1007/s11856-017-1512-0

Research presentations

  1. Oral presentation(general) Loop components of nontrivial nonnegative solutions for indefinite concave-convex problems 日本数学会2018年年会函数方程式論分科会 2018/03/18
  2. Oral presentation(invited, special) concave-convex タイプの非線形楕円型境界値問題に対するループ型有界連続体解集合の存在について 首都大学東京・変分問題セミナー 2017/12/14
  3. Oral presentation(general) Positivity for nontrivial nonnegative solutions of an indefinite sublinear problem 日本数学会2017年年会函数方程式論分科会 2017/03/24
  4. Oral presentation(invited, special) On the existence of a loop component of nontrivial non-negative solutions for some concave-convex problem Workshop on reaction diffusion equations and numerical analysis 2016/10/08
  5. Oral presentation(invited, special) A loop type component of positive solutions of an indefinite concave-convex problem with the Neumann boundary condition The 11th AIMS Conference on Dynamical Systems, Differential Equations and Applications in Orlando 2016/07/04


  1. The ISAAC Award for Young Scientists 2003/08 URL http://mathisaac.org/c/serverisaac/2007/03.html

Memberships of academic societies

  1. 日本数学会
  2. 日本応用数理学会