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arXiv 1805.02853math.AP
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三维微极流体系统在Fourier-Besov空间中的尖锐适定性适定性与不适定性

Sharp well-posedness and ill-posedness for the 3-D micropolar fluid system in Fourier-Besov spaces

Weipeng Zhu

摘要:

研究了$\mathbb{R}^{3}$中不可压缩微极流体系统的Cauchy问题。在第一作者和赵继红\cite{ZhuZ18}的近期工作中,证明了不可压缩微极流体系统的Cauchy问题对于$1<p\leq\infty$和$1\leq r<\infty$在Fourier-Besov空间$\F^{2-\frac{3}{p}}_{p,r}$中是局部适定的,而对于小初值在这些空间中是整体适定的.在这项工作中,我们认为关键的情况下$p=1$。我们证明了这个问题在$1\leq r\leq 2$的$\F^{-1}_{1,r}$中是局部适定的,并且在这些空间中是全局适定的。进一步证明了该问题在$2< r\leq \infty$中是不适定的,这意味着函数空间$\F^{-1}_{1,2}$是适定性的尖的。此外,利用类似的论证,我们还证明了该问题在Besov空间$\B^{-1}_{\infty,r}$中是不适定的,其中$2<r\leq\infty$ .

英文摘要:

We study the Cauchy problem of the incompressible micropolar fluid system in $\mathbb{R}^{3}$. In a recent work of the first author and Jihong Zhao \cite{ZhuZ18}, it is proved that the Cauchy problem of the incompressible micropolar fluid system is locally well-posed in the Fourier--Besov spaces $\F^{2-\frac{3}{p}}_{p,r}$ for $1<p\leq\infty$ and $1\leq r<\infty$, and globally well-posed in these spaces with small initial data. In this work we consider the critical case $p=1$. We show that this problem is locally well-posed in $\F^{-1}_{1,r}$ for $1\leq r\leq 2$, and is globally well-posed in these spaces with small initial data. Furthermore, we prove that such problem is ill-posed in $\F^{-1}_{1,r}$ for $2< r\leq \infty$, which implies that the function space $\F^{-1}_{1,2}$ is sharp for well-posedness. In addition, using a similar argument we also prove that this problem is ill-posed in the Besov space $\B^{-1}_{\infty,r}$ with $2<r\leq\infty$.

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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