Kanazawa Analysis Seminar
Modeling chemotaxis and cell aggregation by a parabolic system of PDEs, the Keller-Segel system has played a pivotal role in mathematical biology for over 50 years. Besides its possible blowup in finite time and various modeling applications, e.g., in tumor progression, a mathematical aspect of interest is its numerical discretization, which has been a challenge due to localized high concentrations appearing in the solutions. In this talk we review the model and its prominent properties and introduce new a posteriori estimates that lay the foundation of adaptive mesh refinement schemes. The results are based on stability estimates and suitable reconstructions of the numerical solution. We also discuss implications on well-posedness, provide estimates for modified cell migration models and elucidate the behavior of the error estimator in numerical experiments.
* This is joint work with Jan Giesselmann and Kiwoong Kwon from the Technical University of Darmstadt.
The p-Sobolev flow is the gradient flow associated with the Sobolev inequality and is described as a doubly nonlinear parabolic equation. In the case p=2 the p-Sobolev flow much related to the Yamabe flow. The asymptotic behavior at infinite-time of the p-Sobolev flow will be studied. We present the global existence for Cauchy-Dirichlet problem for the pSobolev flow, a boundedness, a positivity and a regularity of the solution. The local boundedness is the new ingredient obtained for the doubly nonlinear parabolic equation and the key for studying the energy-volume concentration phenomenon at infinite-time of the pSobolev flow. Our global existence of the p-Sobolev flow is based on the scaling transformation intrinsic to the doubly nonlinear parabolic equation and this our approach also eventually leads to an aplication to the finite-time extinction-behavior for the so-called fast and fast diffusive doubly nonlinear parabolic equation. This is based on a collaborative work with Tuomo Kuusi in University of Helsinki, Finland and Kenta Nakamura in Kumamoto University.
References:
T. Kuusi, M. Misawa, K. Nakamura: J. Geom. Anal. 30 (2020) 1918-1964;
J.Differ. Equ. 279 (2021) 245-281;
M. Misawa, K. Nakamura: Adv. Calc. Var. (2021); J. Geom.Anal. 33: 33
(2023);
M. Misawa, K. Nakamura, Md Abu Hanif Sarkar: Nonlinear Differ. Eqn.
Appl. 30 ; 43 (2023);
M. Misawa: Calc. Var. 62 (2023), no. 9, No. 265
2013年4月,金沢大学の偏微分方程式研究者有志が集まり本セミナーを企画しました。各回の話題は,偏微分方程式の理論的な側面を中心に,セミナー幹事の関心に従い大らかに選択しています。参加者がセミナーを十分楽しみ,勉強し,新しい発見を得られるように,各回の最初の20分から30分程度,講演者の方にはその話題への導入となるような解説をお願いしています。ご関心がある方はどなたでもご自由にご参加ください。 どうぞよろしくお願いいたします。
Patrick van Meurs・大塚 浩史・小俣 正朗・蚊戸 宣幸・木村 正人・榊原 航也・Thomas Geert De Jong・野津 裕史・Norbert Pozar・Julius Fergy Tiongson Rabago
npozar (at) se.kanazawa-u.ac.jp