@article{onlinecovarianceestimationinaveragedsgdi,
  title = {Online Covariance Estimation in Averaged SGD: Improved Batch-Mean Rates and Minimax Optimality via Trajectory Regression},
  author = {Yijin Ni and Xiaoming Huo},
  year = {2026},
  eprint = {2604.10814},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2604.10814},
}