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arXiv 1210.0957math.DG
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直径控制与远离奇异集的光滑收敛

Diameter Controls and Smooth Convergence away from Singular Sets

Sajjad Lakzian

摘要:

本文证明了:如果紧黎曼流形$M^n$上的度量族$g_i$有一致的Ricci曲率下界,且在Hausdorff测度$H^{n-1}(S) = 0$下,从奇异集$S$光滑收敛到$g_\infty$,且存在满足$\diam_{g_i}(M^n) \le D_0 $的$M^n \setminus S$的连通预紧穷竭$W_j$,$\vol_{g_i}(\partial W_j) \le A_0 $和$\vol_{g_i}(M^n \setminus W_j) \le V_j where \lim_{j\to\infty}V_j=0 $则Gromov-Hausdorff极限存在,并且与$(M^n \setminus S, g_\infty)$的度量完备性一致。回想一下,在以前的工作与Sormani得出相同的结论,但奇异集被假定为一个子流形的余维2。我们有第二个主要定理,其中$S$上的Hausdorff测度条件被耗尽边界$\partial W_j$的连通分量上的直径估计所取代。此外,我们证明了这些定理中的一致Ricci曲率下界可以用一致线性可压缩函数的存在性来代替。如果这个条件被完全删除,那么我们证明了$\lim_{j\to \infty} d_{\mathcal{F}}(M_j', N')=0$,其中$M_j'$和$N'$是$(M, g_j)$和$(M_\infty\setminus S, g_\infty)$分别解决完成和$d_{\mathcal{F}}$是Sormani-Wenger内在平坦距离。我们提出的例子证明了我们的定理中的许多假设的必要性。

英文摘要:

We prove that if a family of metrics, $g_i$, on a compact Riemannian manifold, $M^n$, have a uniform lower Ricci curvature bound and converge to $g_\infty$ smoothly away from a singular set, $S$, with Hausdorff measure, $H^{n-1}(S) = 0$, and if there exists connected precompact exhaustion, $W_j$, of $M^n \setminus S$ satisfying $\diam_{g_i}(M^n) \le D_0 $, $\vol_{g_i}(\partial W_j) \le A_0 $ and $\vol_{g_i}(M^n \setminus W_j) \le V_j where \lim_{j\to\infty}V_j=0 $ then the Gromov-Hausdorff limit exists and agrees with the metric completion of $(M^n \setminus S, g_\infty)$. Recall that in the prior work with Sormani the same conclusion is reached but the singular set is assumed to be a submanifold of codimension two. We have a second main theorem in which the Hausdorff measure condition on $S$ is replaced by diameter estimates on the connected components of the boundary of the exhaustion, $\partial W_j$. In addition, we show that the uniform lower Ricci curvature bounds in these theorems can be replaced by the existence of a uniform linear contractibility function. If this condition is removed altogether, then we prove that $\lim_{j\to \infty} d_{\mathcal{F}}(M_j', N')=0$, in which $M_j'$ and $N'$ are the settled completions of $(M, g_j)$ and $(M_\infty\setminus S, g_\infty)$ respectively and $d_{\mathcal{F}}$ is the Sormani-Wenger Intrinsic Flat distance. We present examples demonstrating the necessity of many of the hypotheses in our theorems.

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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