“…Since being proposed, MC has received great attention from scientists in many fields [31,32,33]. In the past 20 years, both the theory [32,34,35,36,37] and application [31,38,39,40,41] of MC have been greatly developed, and many different classes of P systems have been investigated. According to the way in which membranes are structured, there are three major types of P systems, i.e., cell-like [19], tissue-like [42] and spiking neural P systems [43,44].…”