“…Finally, the online optimization algorithm can be used to train SDE models (including point process models) of limit order books (Bellani et al, 2021;Kumar, 2021;Lu and Abergel, 2018;Morariu-Patrichi & Pakkanen, 2022;Shi & Cartlidge, 2022). Order books involve large numbers of high-frequency events (∼ 10 5 − 10 6 events per day per stock) and high-dimensional dynamics (many price levels, each with limit order submissions and cancellations, as well as market orders, hidden orders, and transactions).…”