{ "id": "1701.02817", "version": "v1", "published": "2017-01-11T01:01:26.000Z", "updated": "2017-01-11T01:01:26.000Z", "title": "A unified method for boundedness in fully parabolic chemotaxis systems with signal-dependent sensitivity", "authors": [ "Masaaki Mizukami", "Tomomi Yokota" ], "comment": "15pages", "categories": [ "math.AP" ], "abstract": "This paper deals with the Keller--Segel system with signal-dependent sensitivity \\begin{equation*} u_t=\\Delta u - \\nabla \\cdot (u \\chi(v)\\nabla v), \\quad v_t=\\Delta v + u - v, \\quad x\\in\\Omega,\\ t>0, \\end{equation*} where $\\Omega$ is a bounded domain in $\\mathbb{R}^n$, $n\\geq 2$; $\\chi$ is a function satisfying $\\chi(s)\\leq K(a+s)^{-k}$ for some $k\\geq 1$ and $a\\geq 0$. In the case that $k=1$, Fujie (J. Math. Anal. Appl.; 2015; 424; 675--684) established global existence of bounded solutions under the condition $K<\\sqrt{\\frac{2}{n}}$. On the other hand, when $k>1$, Winkler (Math. Nachr.; 2010; 283; 1664--1673) asserted global existence of bounded solutions for arbitrary $K>0$. However, there is a gap in the proof. Recently, Fujie tried modifying the proof; nevertheless it also has a gap. It seems to be difficult to show global existence of bounded solutions for arbitrary $K>0$. Moreover, the condition for $K$ when $k>1$ cannot connect to the condition when $k=1$. The purpose of the present paper is to obtain global existence and boundedness under more natural and proper condition for $\\chi$ and to build a mathematical bridge between the cases $k=1$ and $k>1$.", "revisions": [ { "version": "v1", "updated": "2017-01-11T01:01:26.000Z" } ], "analyses": { "subjects": [ "35K51", "35B45", "35A01", "92C17" ], "keywords": [ "fully parabolic chemotaxis systems", "signal-dependent sensitivity", "unified method", "bounded solutions", "boundedness" ], "note": { "typesetting": "TeX", "pages": 15, "language": "en", "license": "arXiv", "status": "editable" } } }