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arXiv 2209.02168math.DG
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H型叶理上次Laplacian的局部不变量和几何

Local Invariants and Geometry of the sub-Laplacian on H-type Foliations

Wolfram Bauer, Irina Markina, Abdellah Laaroussi, Gianmarco Vega-Molino

摘要:

本文在亚黎曼几何的框架下研究了$H$型叶理$(\mathbb{M},\mathcal{H},g_{\mathcal{H}})$,其中括号生成分布定义为横截纤维的丛。装备$\mathbb{M}$与Bott连接,我们考虑标量水平曲率$κ_{\mathcal{H}}$以及一个新的局部不变量$τ_{\mathcal{V}}$诱导的垂直分布。本文推广了A。Laaroussi和我们把亚黎曼几何中的第二热不变量表示为$κ_{\mathcal{H}}$和$τ_{\mathcal{V}}$的线性组合。在黎曼几何中使用一个与$H$型叶理的几何结构相适应的法坐标的类比,使我们能够考虑柯拉尼球到$\mathbb{M}$的拉回。我们明确地获得了前三项在小半径的波普体积的渐近展开。最后,我们讨论了当$\mathbb{M}$作为次黎曼流形局部等距于它的$H$型切群时的问题.

英文摘要:

$H$-type foliations $(\mathbb{M},\mathcal{H},g_{\mathcal{H}})$ are studied in the framework of sub-Riemannian geometry with bracket generating distribution defined as the bundle transversal to the fibers. Equipping $\mathbb{M}$ with the Bott connection we consider the scalar horizontal curvature $κ_{\mathcal{H}}$ as well as a new local invariant $τ_{\mathcal{V}}$ induced from the vertical distribution. We extend recent results on the small-time asymptotics of the sub-Riemannanian heat kernel on quaternion-contact (qc-)manifolds due to A. Laaroussi and we express the second heat invariant in sub-Riemannian geometry as a linear combination of $κ_{\mathcal{H}}$ and $τ_{\mathcal{V}}$. The use of an analog to normal coordinates in Riemannian geometry that are well-adapted to the geometric structure of $H$-type foliations allows us to consider the pull-back of Korányi balls to $\mathbb{M}$. We explicitly obtain the first three terms in the asymptotic expansion of their Popp volume for small radii. Finally, we address the question of when $\mathbb{M}$ is locally isometric as a sub-Riemannian manifold to its $H$-type tangent group.

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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