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High-dimensional data arise routinely in modern statistics, econometrics, finance, genomics, and machine learning. While a large body of existing methodology is developed under Gaussian or light-tailed assumptions, many real data sets…

Methodology · Statistics 2026-04-16 Long Feng

We present a fast, differentially private algorithm for high-dimensional covariance-aware mean estimation with nearly optimal sample complexity. Only exponential-time estimators were previously known to achieve this guarantee. Given $n$…

Machine Learning · Computer Science 2025-11-26 Gavin Brown , Samuel B. Hopkins , Adam Smith

We consider the problem of finding a dense submatrix of a matrix with i.i.d. Gaussian entries, where density is measured by average value. This problem arose from practical applications in biology and social sciences…

Probability · Mathematics 2025-07-28 Shankar Bhamidi , David Gamarnik , Shuyang Gong

High-dimensional linear regression under heavy-tailed noise or outlier corruption is challenging, both computationally and statistically. Convex approaches have been proven statistically optimal but suffer from high computational costs,…

Statistics Theory · Mathematics 2023-05-11 Yinan Shen , Jingyang Li , Jian-Feng Cai , Dong Xia

We propose an estimator for the mean of a random vector in $\mathbb{R}^d$ that can be computed in time $O(n^4+n^2d)$ for $n$ i.i.d.~samples and that has error bounds matching the sub-Gaussian case. The only assumptions we make about the…

Statistics Theory · Mathematics 2019-02-07 Yeshwanth Cherapanamjeri , Nicolas Flammarion , Peter L. Bartlett

In this paper, we study robust covariance estimation under the approximate factor model with observed factors. We propose a novel framework to first estimate the initial joint covariance matrix of the observed data and the factors, and then…

Methodology · Statistics 2016-02-03 Jianqing Fan , Weichen Wang , Yiqiao Zhong

This work builds upon previous efforts in online incremental learning, namely the Incremental Gaussian Mixture Network (IGMN). The IGMN is capable of learning from data streams in a single-pass by improving its model after analyzing each…

Machine Learning · Computer Science 2017-02-08 Rafael Pinto , Paulo Engel

We study the algorithmic problem of estimating the mean of heavy-tailed random vector in $\mathbb{R}^d$, given $n$ i.i.d. samples. The goal is to design an efficient estimator that attains the optimal sub-gaussian error bound, only assuming…

Statistics Theory · Mathematics 2020-02-19 Zhixian Lei , Kyle Luh , Prayaag Venkat , Fred Zhang

This paper studies the Gaussian approximation of high-dimensional and non-degenerate U-statistics of order two under the supremum norm. We propose a two-step Gaussian approximation procedure that does not impose structural assumptions on…

Statistics Theory · Mathematics 2016-10-04 Xiaohui Chen

A continuous-time regression model with a jointly strictly sub-Gaussian random noise is considered in the paper. Upper exponential bounds for probabilities of large deviations of the least squares estimator for the regression parameter are…

Probability · Mathematics 2018-06-12 Alexander V. Ivanov , Igor V. Orlovskyi

A current strand of research in high-dimensional statistics deals with robustifying the available methodology with respect to deviations from the pervasive light-tail assumptions. In this paper we consider a linear mean regression model…

Statistics Theory · Mathematics 2025-02-06 Philipp Hermann , Hajo Holzmann

This paper provides some extended results on estimating parameter matrix of several regression models when the covariate or response possesses weaker moment condition. We study the $M$-estimator of Fan et al. (Ann Stat 49(3):1239--1266,…

Statistics Theory · Mathematics 2022-09-08 Kangqiang Li , Songqiao Tang , Lixin Zhang

We study the fundamental problem of estimating the mean of a $d$-dimensional distribution with covariance $\Sigma \preccurlyeq \sigma^2 I_d$ given $n$ samples. When $d = 1$, \cite{catoni} showed an estimator with error $(1+o(1)) \cdot…

Statistics Theory · Mathematics 2024-02-20 Shivam Gupta , Samuel B. Hopkins , Eric Price

We study the problem of linear regression where both covariates and responses are potentially (i) heavy-tailed and (ii) adversarially contaminated. Several computationally efficient estimators have been proposed for the simpler setting…

Statistics Theory · Mathematics 2021-05-18 Ankit Pensia , Varun Jog , Po-Ling Loh

We propose methodology for statistical inference for low-dimensional parameters of sparse precision matrices in a high-dimensional setting. Our method leads to a non-sparse estimator of the precision matrix whose entries have a Gaussian…

Statistics Theory · Mathematics 2015-08-13 Jana Jankova , Sara van de Geer

This paper investigates the iterates $\hbb^1,\dots,\hbb^T$ obtained from iterative algorithms in high-dimensional linear regression problems, in the regime where the feature dimension $p$ is comparable with the sample size $n$, i.e., $p…

Machine Learning · Statistics 2024-04-30 Pierre C. Bellec , Kai Tan

In this paper, we develop connections between two seemingly disparate, but central, models in robust statistics: Huber's epsilon-contamination model and the heavy-tailed noise model. We provide conditions under which this connection…

Machine Learning · Statistics 2019-07-03 Adarsh Prasad , Sivaraman Balakrishnan , Pradeep Ravikumar

We address the problem of robust sparse estimation of the precision matrix for heavy-tailed distributions in high-dimensional settings. In such high-dimensional contexts, we observe that the covariance matrix can be approximated by a…

Methodology · Statistics 2025-03-06 Zhengke Lu , Long Feng

The accurate specification of the number of factors is critical to the validity of factor models and the topic almost occupies the central position in factor analysis. Plenty of estimators are available under the restrictive condition that…

Methodology · Statistics 2019-08-15 Long Yu , Yong He , Xinsheng Zhang

We propose, for multivariate Gaussian copula models with unknown margins and structured correlation matrices, a rank-based, semiparametrically efficient estimator for the Euclidean copula parameter. This estimator is defined as a one-step…

Methodology · Statistics 2014-10-02 Johan Segers , Ramon van den Akker , Bas J. M. Werker