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arXiv 1906.00720math.AP
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带临界加权反应项的反应扩散方程的爆破解型

Blow up profiles for a reaction-diffusion equation with critical weighted reaction

Razvan Gabriel Iagar, Ariel Sánchez

AI总结:

本研究分类了带权重|x|^σ的反应扩散方程的自相似爆破解型,发现σ较小时存在任意多的带界面紧支集爆破解型,σ足够大时这类解型不存在,且对任意σ>0都无全空间支集的爆破解型。

摘要:

我们对如下带加权反应项的反应扩散方程的自相似爆破解型进行分类:$$ u_t=(u^m)_{xx} + |x|^σu^m, $$ 其定义域为 $(x,t)\in\real\times(0,T)$,其中 $m>1$ 且 $σ>0$。与已被充分研究的无权重方程(即 $σ=0$ 的情况)形成强烈对比的是,一方面我们证明,当 $σ>0$ 足够小时,存在多个在有限点处带界面的自相似解型;更确切地说,给定任意正整数 $k$,存在 $δ_k>0$,使得当 $σ∈(0,δ_k)$ 时,至少存在 $k$ 种不同的、具有紧支集且在正点处带界面的爆破解型。另一方面我们还证明,当 $σ$ 足够大时,带界面的自相似爆破解型不再存在。当 $σ>0$ 增大时,多解存在性与无任何解存在性之间这种出人意料的平衡,源于权重 $|x|^σ$ 的存在所产生的效应,研究该权重的影响正是本研究的主要目标。我们还证明,对于任意 $σ>0$,不存在支集覆盖全空间的爆破解型,即不存在对任意 $x∈\real$ 和 $t∈(0,T)$ 都满足 $u(x,t)>0$ 的解型。

英文摘要:

We classify the blow up self-similar profiles for the following reaction-diffusion equation with weighted reaction $$ u_t=(u^m)_{xx} + |x|^σu^m, $$ posed for $(x,t)\in\real\times(0,T)$, with $m>1$ and $σ>0$. In strong contrast with the well-studied equation without the weight (that is $σ=0$), on the one hand we show that for $σ>0$ sufficiently small there exist \emph{multiple self-similar profiles with interface} at a finite point, more precisely, given any positive integer $k$, there exists $δ_k>0$ such that for $σ\in(0,δ_k)$, there are at least $k$ different blow up profiles with compact support and interface at a positive point. On the other hand, we also show that for $σ$ sufficiently large, the blow up self-similar profiles with interface \emph{cease to exist}. This unexpected balance between existence of multiple solutions and non-existence of any, when $σ>0$ increases, is due to the effect of the presence of the weight $|x|^σ$, whose influence is the main goal of our study. We also show that for any $σ>0$, there are no blow up profiles supported in the whole space, that is with $u(x,t)>0$ for any $x\in\real$ and $t\in(0,T)$.

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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