Working Papers
Working Papers
Steady-State Convergence of Stochastic Approximation (Job Market Paper)
Yixuan Zhang, and Qiaomin Xie
First Place, ACM SIGMETRICS 2026 Student Research Competition
Yixuan Zhang, and Qiaomin Xie
Gaussian Approximation in Wasserstein-1: Local Dependence and Markovian Martingale Differences
Yixuan Zhang, and Qiaomin Xie
Journal Revisions and Publications
A Unified Lyapunov Analysis for Sub-quadratic-SGD: Applications to Robust and Quantile Regression
Yixuan Zhang, Lucy Huo, and Qiaomin Xie
Preliminary version: ACM SIGMETRICS 2025
Major revision at Stochastic Systems
Satisficing Regret Minimization under Nonstationarity
Yixuan Zhang, Ruihao Zhu, and Qiaomin Xie
Major revision at Operations Research
Finalist, INFORMS 2026 Data Mining Society Best Paper Award Competition (Student Track).
Preliminary version: NeurIPS 2026 Second Workshop on MLxOR
Memory, Nonlinearity, and Drift–Contraction in Stochastic Approximation with a Constant Stepsize
Yixuan Zhang, Lucy Huo, and Qiaomin Xie
Major revision at Mathematics of Operations Research
Preliminary version: NeurIPS 2024 (Spotlight)
Prelimit Coupling and Steady-State Convergence of Constant-stepsize Nonsmooth Contractive SA
Yixuan Zhang, Lucy Huo, Yudong Chen, and Qiaomin Xie
Operations Research, 2026
Preliminary version: ACM SIGMETRICS 2024
Conference Publications
Wasserstein-p Central Limit Theorem Rates: From Local Dependence to Markov Chains
Yixuan Zhang, and Qiaomin Xie
ACM SIGMETRICS 2026
Best Student Paper Award and Best Paper Finalist, ACM SIGMETRICS 2026.
Contextual Online Pricing with (Biased) Offline Data
Yixuan Zhang, Ruihao Zhu, and Qiaomin Xie
NeurIPS 2025
A Piecewise Lyapunov Analysis of Sub-quadratic SGD: Applications to Robust and Quantile Regression
Yixuan Zhang, Lucy Huo, Yudong Chen, and Qiaomin Xie
ACM SIGMETRICS 2025
The Collusion of Memory and Nonlinearity in Stochastic Approximation With Constant Stepsize
Lucy Huo, Yixuan Zhang, Yudong Chen, and Qiaomin Xie
NeurIPS 2024 (Spotlight)
Prelimit Coupling and Steady-State Convergence of Constant-stepsize Nonsmooth Contractive SA
Yixuan Zhang, Lucy Huo, Yudong Chen, and Qiaomin Xie
ACM SIGMETRICS 2024 [video]
Constant Stepsize Q-learning: Distributional Convergence, Bias and Extrapolation
Yixuan Zhang, and Qiaomin Xie
Reinforcement Learning Conference 2024