西谷達雄, Nishitani Tatsuo
Professor Emeritus
Department of Mathematics
Osaka University
Toyonaka, Osaka 560-0043
JAPAN

E-mail: nishitani@math.sci.osaka-u.ac.jp

• @google scholar

• Notes on geometric aspects of effectively hyperbolic critical points when the characteristic roots are real on one side of time, Proc. Japan Acad. Ser. A Math.Sci. (2024) OpenAccess
• A more direct way to the Cauchy problem for effectively hyperbolic operators, J. Pseudo-Differ. Oper. Appl. (2024) shared link
• Cauchy problem for operators with triple effectively hyperbolic characteristics--Ivrii's conjecture--, J. Anal. Math. (2023) shared link
• A discrete algorithm for general weakly hyperbolic systems (with Ferruccio Colombini and Jeffrey Rauch) J. Pseudo-Differ. Oper. Appl. (2022) shared link
• Diagonal symmetrizers for hyperbolic operators with triple characteristics Mathematishe Annalen (2021) shared link
• Transversally strictly hyperbolic systems, Kyoto J. Math. 60 (2020), 1399-1418 pdf
• On the Cauchy problem for D_t^2-D_x(b(t)a(x))D_x, Journal of Hyperbolic Differential Equations (2020), 75-122 (with Ferruccio Colombini)
• Cauchy problem for hyperbolic operators with triple effective characteristics on the initial plane, Osaka J. Math. 57 (2020), 597-615 (with Vesselin Petkov)
• Notes on symmetrization by Bezoutian, Bollettino dell'Unione Matematica Italiana (2020) 13: 417-428 link
• Cauchy problem for effectively hyperbolic operators with triple characteristics, J. Math. Pures Appl., 123 (2019), 201-228 (with Vesselin Petkov)
• Weakly hyperbolic systems by symmetrization, Ann. Sci. Norm. Super. Pisa XIX (2019), 217-251 (with Ferruccio Colombini and Jeffrey Rauch)
• Note on strongly hyperbolic systems with involute characteristics, Kyoto J. Math., 58 (2018), 569-582 (with Guy M\'etivier) pdf

• arXiv
• A direct energy estimates for effectively hyperbolic operators pdf
• Cauchy problem for operators with triple effectively hyperbolic characteristics--Ivrii's conjecture-- arxiv

• The Cauchy problem for differential operators with double characteristics, Sugaku Expositions, AMS. 31(2018)pdf
• 二次特性的双曲型偏微分方程式の初期値問題の適切性(数学，2014) download
• Effectively hyperbolic Cauchy problem (Lectures at De Giorgi Center, 2004) pdf
• Hyperbolic equations with double characteristics (Lectures at University of Pisa, 2000) pdf
• Hyperbolic Systems with Two Independent Variables (Lectures at Tsukuba University, 1999) pdf
• 強双曲系ーその必要条件を探る(Lectures at Ryukoku University, 1997) pdf
• The hyperbolic Cauchy problem (Lectures at Seoul National University, 1992) pdf
• 基礎教養 pdf
• Calculus pdf
• Lebesgue 積分 pdf
• 擬微分作用素 pdf

• Examples of uniformly symmetrizable systems for which the Cauchy problem is ill-posed in the Gevrey class >2 (February, 2024) slides
• Applications of pseudodifferential operators of symbol exp(S^{\kappa}_{\rho,\delta}) to the Cauchy problem (February, 2024)pdf
• On pseudodifferential operators of symbol exp(S^{\kappa}_{\rho,\delta}) (January, 2024)pdf
• exp(S^{\kappa}_{\rho,\delta})型Gevrey擬微分作用素について (October, 2023)pdf
• A note on time functions associated with effectively hyperbolic double characteristics (March, 2022) pdf
• Notes on tangent bicharacteristics and transition of the spectral type of the Hamilton map (April, 2022) pdf
• A note on the Cauchy problem for -D₀²+2x₁D₀D₂+D₁²+x₁³D₂²+b₀D₀+b₁D₁+b₂D₂ (March, 2022) pdf
• A question on the Cauchy problem in the Gevrey classes for weakly hyperbolic equations (July, 2022) pdf

• 実効的双曲型作用素の初期値問題 (数学メモアール, 2024)
• Cauchy Problem for Differential Operators with Double Characteristics (LNM, Springer, 2017)
• Corrections
• 線形双曲型偏微分方程式 (朝倉書店, 2015)
• 正誤表
• Hyperbolic Systems With Analytic Coefficients (LNM, Springer, 2014)
• Corrections
• Cauchy Problem for Noneffectively Hyperbolic Operators (MSJ Memoirs, 2013)
• Corrections
• The effectively hyperbolic Cauchy problem (LNM, Springer, 1991)

Last modified: June 18, 2024