arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2007.13909math.AP
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半空间中的反应扩散方程

Reaction-diffusion equations in the half-space

Henri Berestycki, Cole Graham

摘要:

本文研究半空间中各种类型的反应扩散方程。对于Dirichlet边界条件下的反应,我们证明了条件唯一性:在大球上存在唯一的非零有界稳定态,该稳定态超过了Dirichlet阈值。此外,从足够大的初始数据开始的解收敛到该稳态为$t \to \infty$。对于压缩的初始数据,这种传播的渐近速度与一维行波的唯一速度$c_*$一致。我们还在速度半平面$c_*$中构造了一个行波。在平行,我们表现出类似的结果下的Dirichlet和罗宾边界条件的点火反应。使用我们的点火结构,我们得到了更强的单稳态反应具有相同的边界条件。对于这样的反应,我们表明,在一般情况下,有一个唯一的非零有界稳态。此外,单稳态反应表现出一触即发的效果:每个解决方案与非平凡的初始数据收敛到这个稳定状态$t \to \infty$。在给定的初始数据的情况下,这种扰动以等于一维行波的最小速度的速度$c_*$传播。我们还构造了Dirichlet或Robin半平面中任意速度的单稳行波$c \geq c_*$。

英文摘要:

We study reaction-diffusion equations of various types in the half-space. For bistable reactions with Dirichlet boundary conditions, we prove conditional uniqueness: there is a unique nonzero bounded steady state which exceeds the bistable threshold on large balls. Moreover, solutions starting from sufficiently large initial data converge to this steady state as $t \to \infty$. For compactly supported initial data, the asymptotic speed of this propagation agrees with the unique speed $c_*$ of the one-dimensional traveling wave. We furthermore construct a traveling wave in the half-plane of speed $c_*$. In parallel, we show analogous results for ignition reactions under both Dirichlet and Robin boundary conditions. Using our ignition construction, we obtain stronger results for monostable reactions with the same boundary conditions. For such reactions, we show in general that there is a unique nonzero bounded steady state. Furthermore, monostable reactions exhibit the hair-trigger effect: every solution with nontrivial initial data converges to this steady state as $t \to \infty$. Given compactly supported initial data, this disturbance propagates at a speed $c_*$ equal to the minimal speed of one-dimensional traveling waves. We also construct monostable traveling waves in the Dirichlet or Robin half-plane with any speed $c \geq c_*$.

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