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arXiv 1204.6434math.AP
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欧几里得空间中快速扩散的高阶时间渐近性:一个动力系统方法

Higher order time asymptotics of fast diffusion in euclidean space: a dynamical systems approach

Jochen Denzler, Herbert Koch, Robert McCann

摘要:

本文量化了R^n上快扩散动力系统到Barenblatt(自相似)解的收敛速度和高阶渐近性。这个方程的抛物性退化是通过在一个有圆柱形末端的流形上重新表达动力学来治愈的,这个流形被称为雪茄。非线性演化在雪茄上的Hoelder空间中变得可微。动力学的线性化由Laplace-Beltrami算子加上传输项(其可以通过在函数空间范数中引入适当的权重来抑制)加上具有通用轮廓的有限深度势阱给出。在(线性)热方程的极限情况下,深度发散,本征态的数目无限制地增加,并且连续谱后退到无穷大。我们提供了一个详细的研究的线性和非线性问题的Hoelder空间的雪茄,包括一个尖锐的有界估计的半群,并以此为工具,以获得尖锐的收敛结果向Barenblatt解决方案,高阶渐近。在更精细的收敛结果中(在修改了问题的对称性之后),揭示了收敛速度和尾部行为之间的微妙相互作用。选择正确的函数空间进行分析所涉及的困难可以被解释为方程的真正特征,而不仅仅是令人讨厌的技术细节。

英文摘要:

This paper quantifies the speed of convergence and higher- order asymptotics of fast diffusion dynamics on R^n to the Barenblatt (self similar) solution. Degeneracies in the parabolicity of this equation are cured by re-expressing the dynamics on a manifold with a cylindrical end, called the cigar. The nonlinear evolution becomes differentiable in Hoelder spaces on the cigar. The linearization of the dynamics is given by the Laplace-Beltrami operator plus a transport term (which can be suppressed by introducing appropriate weights into the function space norm), plus a finite-depth potential well with a universal profile. In the limiting case of the (linear) heat equation, the depth diverges, the number of eigenstates increases without bound, and the continuous spectrum recedes to infinity. We provide a detailed study of the linear and nonlinear problems in Hoelder spaces on the cigar, including a sharp boundedness estimate for the semi-group, and use this as a tool to obtain sharp convergence results toward the Barenblatt solution, and higher order asymptotics. In finer convergence results (after modding out symmetries of the problem), a subtle interplay between convergence rates and tail behavior is revealed. The difficulties involved in choosing the right functional spaces in which to carry out the analysis can be interpreted as genuine features of the equation rather than mere annoying technicalities.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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