论文标题

双线非线性反应扩散方程中的旅行波行为

Travelling-wave behaviour in doubly nonlinear reaction-diffusion equations

论文作者

Du, Yihong, Garriz, Alejandro, Quiros, Fernando

论文摘要

我们研究了一个反应扩散方程的家族,该家族表现出由$ p $ laplacian和多孔媒体操作员的组合给出的双重非线性特征。我们考虑了所谓的慢散射状态,对应于在0级的堕胎行为,\ normalColor,其中具有紧凑型初始数据的非负溶液在任何以后的时间都具有紧凑的支持。对于某些结果,我们还将需要$ p \ ge2 $,以避免从0远离奇异行为的可能性。 这个家庭中的问题具有有限阵线的独特(翻译)行驶波。当初始基准受到界限,径向对称和紧凑的支持时,我们将证明解决方案会收敛到1(如我们所示,对于广泛的初始数据所考虑的所有反应术语而存在),通过在径向方向上接近这种独特的行动波的翻译,但是在偏端更大的位置时,在径向方向上的转换。作为推论,我们获得了自由边界和级别集的渐近位置,在非radial情况下达到尺寸$ o(1)$的误差项。在维度一个方面,我们扩展了结果,以涵盖非对称初始数据的情况,以及有界初始数据的情况,其支持集在真实线的一个方向上无限。独立感兴趣的主要技术工具是通量的估计。 即使对于多孔中等方程和$ p $ - laplacian进化方程的特殊情况,我们的结果也是新的。

We study a family of reaction-diffusion equations that present a doubly nonlinear character given by a combination of the $p$-Laplacian and the porous medium operators. We consider the so-called slow diffusion regime, corresponding to a degenerate behaviour at the level 0, \normalcolor in which nonnegative solutions with compactly supported initial data have a compact support for any later time. For some results we will also require $p\ge2$ to avoid the possibility of a singular behaviour away from 0. Problems in this family have a unique (up to translations) travelling wave with a finite front. When the initial datum is bounded, radially symmetric and compactly supported, we will prove that solutions converging to 1 (which exist, as we show, for all the reaction terms under consideration for wide classes of initial data) do so by approaching a translation of this unique traveling wave in the radial direction, but with a logarithmic correction in the position of the front when the dimension is bigger than one. As a corollary we obtain the asymptotic location of the free boundary and level sets in the non-radial case up to an error term of size $O(1)$. In dimension one we extend our results to cover the case of non-symmetric initial data, as well as the case of bounded initial data with supporting sets unbounded in one direction of the real line. A main technical tool of independent interest is an estimate for the flux. Most of our results are new even for the special cases of the porous medium equation and the $p$-Laplacian evolution equation.

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