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arXiv 2103.11034math.AP
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不定常区域上线性增长-扩散方程的精确解和临界性态

Exact Solutions and Critical Behaviour for a Linear Growth-Diffusion Equation on a Time-Dependent Domain

Jane Allwright

摘要:

研究了在一个位置和长度都变化的不定常区间上的线性增长扩散方程。我们证明的边界运动的解决方案,可以找到精确的形式的条件,并推导出在每种情况下的明确表达。接下来,我们证明了在“临界”情况下边界附近的精确行为:当区间的端点以这样一种方式移动时,在边界附近既没有指数增长性,也没有衰减,但解决方案的行为就像一个幂律相对于时间。证明使用基于艾里函数的子解,其参数取决于空间和时间。有趣的链接之间观察到这一结果和Bramson的对数项的非线性FKPP方程的实数线。每个主要定理都被推广到更高的维度,相应的结果与不定常的半径的球。

英文摘要:

A linear growth-diffusion equation is studied in a time-dependent interval whose location and length both vary. We prove conditions on the boundary motion for which the solution can be found in exact form, and derive the explicit expression in each case. Next we prove the precise behaviour near the boundary in a `critical' case: when the endpoints of the interval move in such a way that near the boundary there is neither exponential growth nor decay, but the solution behaves like a power law with respect to time. The proof uses a subsolution based on the Airy function with argument depending on both space and time. Interesting links are observed between this result and Bramson's logarithmic term in the nonlinear FKPP equation on the real line. Each of the main theorems is extended to higher dimensions, with a corresponding result on a ball with time-dependent radius.

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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