“…But transitions from each state i > 0 happen with intensities µ i (t), λ i (t) and β i (t) and can be either to state (i − 1) or (i + 1) or 0, respectively. Such subclass of processes finds its application in the study of queueing systems with catastrophes and bulk arrivals (see, for example, [7,1,3,2,8,5,9,11,4,10]). For more details, concerning possible applications, one can refer to [11] and references therein.…”