“…Many progresses in this topic were made for the low-rank matrix estimation (Keshavan et al, 2009;Boumal andAbsil, 2011, 2015;Wei et al, 2016;Meyer et al, 2011;Mishra et al, 2014;Vandereycken, 2013;Huang and Hand, 2018;Cherian and Sra, 2016;Luo et al, 2020). See the recent survey on this line of work at Cai and Wei (2018); Uschmajew and Vandereycken (2020). Moreover, Riemannian manifold optimization method has been applied for various problems on low-rank tensor estimation, such as tensor regression (Cai et al, 2020;Kressner et al, 2016), tensor completion (Rauhut et al, 2015;Kasai and Mishra, 2016;Dong et al, 2021;Kressner et al, 2014;Heidel and Schulz, 2018;Xia and Yuan, 2017;Steinlechner, 2016;Da Silva and Herrmann, 2015), and robust tensor PCA (Cai et al, 2021).…”