activity
20212026
most citedCatoni-style confidence sequences for heavy-tailed mean estimation

20 citations · 42 across the 13 of their papers we have counts for

collaborators

14 papers

stat.ME2026

M-estimation with e-statistics

Hongjian Wang, Aaditya Ramdas

We present a theory of point estimation with e-statistics (e-values and e-processes) by introducing the "ME-estimator": the parameter that minimizes the corresponding e-statistic,…

math.ST2026

E-values and sequential power-one tests for monotonicity and unimodality

Hongjian Wang, Aaditya Ramdas

We develop e-values and e-processes testing the null hypothesis that a distribution over nonnegative integers is monotone, and that a distribution over integers is unimodal given a…

math.PR2026

Almost sure null bankruptcy of testing-by-betting strategies

Hongjian Wang, Shubhada Agrawal, Aaditya Ramdas

The bounded mean betting procedure serves as a crucial interface between the domains of (1) sequential, anytime-valid statistical inference, and (2) online learning and portfolio s…

stat.ME2025

Anytime-valid FDR control with the stopped e-BH procedure

Hongjian Wang, Sanjit Dandapanthula, Aaditya Ramdas

The recent e-Benjamini-Hochberg (e-BH) procedure for multiple hypothesis testing is known to control the false discovery rate (FDR) under arbitrary dependence between the input e-v…

math.PR2024

Sharp Matrix Empirical Bernstein Inequalities

Hongjian Wang, Aaditya Ramdas

We present two sharp, closed-form empirical Bernstein inequalities for symmetric random matrices with bounded eigenvalues. By sharp, we mean that both inequalities adapt to the unk…

math.ST2024

Testing by Betting while Borrowing and Bargaining

Hongjian Wang, Wouter M. Koolen, Aaditya Ramdas

Testing by betting has been a cornerstone of the game-theoretic statistics literature. One bets against the null hypothesis, and the accumulated wealth quantifies the evidenc…

math.PR2024

Positive Semidefinite Matrix Supermartingales

Hongjian Wang, Aaditya Ramdas

We explore the asymptotic convergence and nonasymptotic maximal inequalities of supermartingales and backward submartingales in the space of positive semidefinite matrices. These a…

math.ST2023★ 1 cited

Time-Uniform Confidence Spheres for Means of Random Vectors

Ben Chugg, Hongjian Wang, Aaditya Ramdas

We study sequential mean estimation in . In particular, we derive time-uniform confidence spheres -- confidence sphere sequences (CSSs) -- which contain the mean of r…

math.ST2023★ 2 cited

Anytime-valid t-tests and confidence sequences for Gaussian means with unknown variance

Hongjian Wang, Aaditya Ramdas

In 1976, Lai constructed a nontrivial confidence sequence for the mean of a Gaussian distribution with unknown variance . Curiously, he employed both an improper (right Ha…

math.PR2023★ 1 cited

The extended Ville's inequality for nonintegrable nonnegative supermartingales

Hongjian Wang, Aaditya Ramdas

Following the initial work by Robbins, we rigorously present an extended theory of nonnegative supermartingales, requiring neither integrability nor finiteness. In particular, we d…

math.ST2023★ 1 cited

Huber-Robust Confidence Sequences

Hongjian Wang, Aaditya Ramdas

Confidence sequences are confidence intervals that can be sequentially tracked, and are valid at arbitrary data-dependent stopping times. This paper presents confidence sequences f…

stat.ML2023★ 7 cited

A unified recipe for deriving (time-uniform) PAC-Bayes bounds

Ben Chugg, Hongjian Wang, Aaditya Ramdas

We present a unified framework for deriving PAC-Bayesian generalization bounds. Unlike most previous literature on this topic, our bounds are anytime-valid (i.e., time-uniform), me…

math.ST2022★ 20 cited

Catoni-style confidence sequences for heavy-tailed mean estimation

Hongjian Wang, Aaditya Ramdas

A confidence sequence (CS) is a sequence of confidence intervals that is valid at arbitrary data-dependent stopping times. These are useful in applications like A/B testing, multi-…

math.OC2021★ 10 cited

Convergence Rates of Stochastic Gradient Descent under Infinite Noise Variance

Hongjian Wang, Mert Gürbüzbalaban, Lingjiong Zhu +2

Recent studies have provided both empirical and theoretical evidence illustrating that heavy tails can emerge in stochastic gradient descent (SGD) in various scenarios. Such heavy…