“…samples. However, in reality, the aggregate number of trades cannot be expected to be unlimitedly small, or close to zero, leading effectively to degeneracy, or trading halts; on the other hand, the long-term trading intensity is generally specified a priori without being optimized and may be estimated in a dynamical fashion using techniques of empirical power variations (see, e.g., [Aït-Sahalia and Jacod, 2009] [3], [Todorov and Tauchen, 2011] [62], [Jing et al, 2012] [34], and [Todorov, 2021] [61]), which of course varies with the frequencies at which data are observed. With restrictions on these two important dimensions, nearly 1 The same processes also play an important role in many nonfinancial fields, especially in reliability engineering to model the degradation phenomena of structural components (see the overview by [Ye and Xie, 2015] [70]).…”