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arXiv 2208.03398math.PRmath.DG
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优化测度的几何方法

Geometric Approach For Majorizing Measures

Shih-Yu Chang

摘要:

高斯过程可以被认为是一个标准希尔伯特空间的子集,但几何的理解,将一个集的大小与其凸包的大小仍然缺乏。在这项工作中,我们采用了一种几何方法的优化措施的问题,通过确定一个给定的空间$T$和它的凸包,由$T_h$表示的覆盖数之间的关系。如果$T$空间是$\mathbb{R}^n$中的一个闭有界多面体,我们可以计算空间$T$与它的凸包之间的体积比,该凸包由Quickhull算法得到。若空间$T$是$\mathbb{R}^n$中的一般紧对象,且内部非空,则首先建立了非凸空间的一个更一般的逆Brunn-Minkowski不等式,如果$T$关于Minkowski和的有限平均可以得到$T_h$,则该不等式将有助于我们用$T$的体积来限制$T_h$的体积.如果得到了空间$T$与空间$T_h$之间的体积比,就可以得到空间$T$与空间$T_h$之间的覆盖数比,并利用覆盖数比建立优化测度不等式.对于无穷维空间,证明了优化测度不等式的常数$L$不一定存在,其存在条件依赖于$T$的几何性质.

英文摘要:

Gaussian processes can be considered as subsets of a standard Hilbert space, but the geometric understanding that would relate the size of a set with the size of its convex hull is still lacking. In this work, we adopt a geometric approach to the majorizing measure problem by identifying the covering number relationships between a given space $T$ and its convex hull, represented by $T_h$. If the space $T$ is a closed bounded polyhedra in $\mathbb{R}^n$, we can evaluate the volume ratio between the space $T$ and its convex hull obtained by the Quickhull algorithm. If the space $T$ is a general compact object in $\mathbb{R}^n$ with non-empty interior, we first establish a more general reverse Brunn-Minkowski inequality for nonconvex spaces which will assist us to bound the volume of $T_h$ in terms of the volume of $T$ if $T_h$ can be acquired by the finite average of the space $T$ with respect to the Minkowski sum. If the volume ratio between the space $T$ and the space $T_h$ is obtained, the covering number ratio between the space $T$ and the space $T_h$ can also be obtained which will be used to build majorizing measure inequality. For infinite dimensional space, we show that the constant $L$ at majorizing measure inequality may not always exist and the existence condition will depend on geometric properties of $T$.

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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