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arXiv 1708.01995math.AP
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Fisher-KPP方程的一个具有给定移动边界的自由边界问题

A free boundary problem for the Fisher-KPP equation with a given moving boundary

Hiroshi Matsuzawa

摘要:

研究Fisher-KPP方程$u_t=u_{xx}+u(1-u),\ t>0,\ ct<x<h(t)$的自由边界问题.数$c>0$是一个给定的常数,$h(t)$是一个自由边界,它由Stefan条件确定。该模型可用于描述非本地物种在一维生境中的扩散。自由边界$x=h(t)$代表扩展前沿。在该模型中,我们在左移动边界$x=ct$处施加零Dirichlet条件。这意味着栖息地的左边界是非常恶劣的环境,并且栖息地被以恒定速度$c$移动的左边界侵蚀掉。本文将给出一个可分性结果,即对于任何初始数据,消失、扩散和跃迁三种行为中的一种恰好发生。这一结果与杜、魏、周等[11](arXiv:1508.06246)关于迁移环境下Fisher-KPP方程的自由边界问题的结果有关。然而,我们的问题中的消失与[11]中的不同,因为在我们的消失情况下,解决方案不是全球性的。

英文摘要:

We study free boundary problem of Fisher-KPP equation $u_t=u_{xx}+u(1-u),\ t>0,\ ct<x<h(t)$. The number $c>0$ is a given constant, $h(t)$ is a free boundary which is determined by the Stefan-like condition. This model may be used to describe the spreading of a non-native species over a one dimensional habitat. The free boundary $x=h(t)$ represents the spreading front. In this model, we impose zero Dirichlet condition at left moving boundary $x=ct$. This means that the left boundary of the habitat is a very hostile environment and that the habitat is eroded away by the left moving boundary at constant speed $c$. In this paper we will give a trichotomy result, that is, for any initial data, exactly one of the three behaviours, vanishing, spreading and transition, happens. This result is related to the results appears in the free boundary problem for the Fisher-KPP equation with a shifting-environment, which was considered by Du, Wei and Zhou [11](arXiv:1508.06246). However the vanishing in our problem is different from that in [11] because in our vanishing case, the solution is not global-in-time.

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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