论文标题
凸锥的高斯随机投影:近似运动公式和应用
Gaussian random projections of convex cones: approximate kinematic formulae and applications
论文作者
论文摘要
了解几何集合的随机投影的随机行为构成了高维概率中的一个基本问题,可以在各种领域中找到广泛的应用。本文为封闭凸锥的高斯随机投影的行为提供了运动描述,类似于[ALMT14]中研究的随机旋转锥的行为。正式地,让$ k $为$ \ mathbb {r}^n $中的封闭凸锥,而$ g \ in \ mathbb {r}^{m \ times n} $是带有i.i.d.的高斯矩阵。 $ \ MATHCAL {N}(0,1)$条目。我们表明,$ gk \ equiv \ {gμ:μ\ in k \} $的行为就像$ \ mathbb {r}^m $具有统计维度$ \ min \ min \ min \ min \ {Δ(Δ(k),m \} $的随机旋转锥体,在以下任何固定的固定封闭的cone $ $ l l $ l l $ l l l $ cone $ l l l l y y $开始{Align*}&δ(l)+δ(k)\ ll m \,\ rightArrow \,l \ cap gk = \ {0 \ {0 \} \ hbox {带有较高的概率},\\&δ(\&δ(l)+Δ(l)+δ(k)+Δ \ hbox {具有高概率}。 \ end {align*}对于$ g^{ - 1} l \ equiv \ {μ\ in \ mathbb {r}^n:gμ\ in L \} $获得了类似的运动描述。 在统计学习,数学编程和渐近几何分析引起的许多不同的问题中证明了规定的近似运动公式的实际实用性和广泛的适用性。 In particular, we prove (i) new phase transitions of the existence of cone constrained maximum likelihood estimators in logistic regression, (ii) new phase transitions of the cost optimum of deterministic conic programs with random constraints, and (iii) a local version of the Gaussian Dvoretzky-Milman theorem that describes almost deterministic, low-dimensional behaviors of subspace sections of randomly projected convex 套。
Understanding the stochastic behavior of random projections of geometric sets constitutes a fundamental problem in high dimension probability that finds wide applications in diverse fields. This paper provides a kinematic description for the behavior of Gaussian random projections of closed convex cones, in analogy to that of randomly rotated cones studied in [ALMT14]. Formally, let $K$ be a closed convex cone in $\mathbb{R}^n$, and $G\in \mathbb{R}^{m\times n}$ be a Gaussian matrix with i.i.d. $\mathcal{N}(0,1)$ entries. We show that $GK\equiv \{Gμ: μ\in K\}$ behaves like a randomly rotated cone in $\mathbb{R}^m$ with statistical dimension $\min\{δ(K),m\}$, in the following kinematic sense: for any fixed closed convex cone $L$ in $\mathbb{R}^m$, \begin{align*} &δ(L)+δ(K)\ll m\, \Rightarrow\, L\cap GK = \{0\} \hbox{ with high probability},\\ &δ(L)+δ(K)\gg m\, \Rightarrow\, L\cap GK \neq \{0\} \hbox{ with high probability}. \end{align*} A similar kinematic description is obtained for $G^{-1}L\equiv \{μ\in \mathbb{R}^n: Gμ\in L\}$. The practical usefulness and broad applicability of the prescribed approximate kinematic formulae are demonstrated in a number of distinct problems arising from statistical learning, mathematical programming and asymptotic geometric analysis. In particular, we prove (i) new phase transitions of the existence of cone constrained maximum likelihood estimators in logistic regression, (ii) new phase transitions of the cost optimum of deterministic conic programs with random constraints, and (iii) a local version of the Gaussian Dvoretzky-Milman theorem that describes almost deterministic, low-dimensional behaviors of subspace sections of randomly projected convex sets.