@inproceedings{xin2018nearly, title={Nearly Optimal Stochastic Approximation for Online Principal Subspace Estimation}, author={Xin Liang, Zhen-Chen Guo, Ren-Cang Li, and Wen-Wei Lin}, url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20171118011441008772855}, year={2018}, }