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arXiv 1401.4385math.AP
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关于Serrin超定问题的一个注记

A note on Serrin's overdetermined problem

Giulio Ciraolo, Rolando Magnanini

摘要:

我们考虑扭转问题$-Δu=1$在$Ω$中的解和$u=0$在$\partial Ω$上的解.塞林著名的对称性定理指出,如果正规导数$u_ν$在$\partial Ω$上是常数,那么$Ω$一定是一个球。在最近的一篇论文中,已经证明Serrin定理可以通过以下方式获得{PDMATHAMR by stability}:首先,对于挠问题的解$u$,证明了对某个常数$C_t$依赖于$t$的估计$$ r_e-r_i\leq C_t\,\Bigl(\max_{Γ_t} u-\min_{Γ_t} u\Bigr) $$,其中$r_e$和$r_i$是包含$\partialΩ$的环的半径,$Γ_t$是在距离$t$处平行于$\partialΩ$且足够接近的表面至$\partialΩ$ ;其次,如果$Ω$上的$u_ν$是常数,证明了$$ \max_{Γ_t} u-\min_{Γ_t} u=o(C_t)\ \mbox{as} \ t\to 0^+. $$本文通过分析一个简单的例子,证明了当$Ω$是椭圆时,该方案是成功的。

英文摘要:

We consider the solution of the torsion problem $-Δu=1$ in $Ω$ and $u=0$ on $\partial Ω$. Serrin's celebrated symmetry theorem states that, if the normal derivative $u_ν$ is constant on $\partial Ω$, then $Ω$ must be a ball. In a recent paper, it has been conjectured that Serrin's theorem may be obtained {\it by stability} in the following way: first, for the solution $u$ of the torsion problem prove the estimate $$ r_e-r_i\leq C_t\,\Bigl(\max_{Γ_t} u-\min_{Γ_t} u\Bigr) $$ for some constant $C_t$ depending on $t$, where $r_e$ and $r_i$ are the radii of an annulus containing $\partialΩ$ and $Γ_t$ is a surface parallel to $\partialΩ$ at distance $t$ and sufficiently close to $\partialΩ$; secondly, if in addition $u_ν$ is constant on $\partialΩ$, show that $$ \max_{Γ_t} u-\min_{Γ_t} u=o(C_t)\ \mbox{as} \ t\to 0^+. $$ In this paper, we analyse a simple case study and show that the scheme is successful if the admissible domains $Ω$ are ellipses.

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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