“…In relation to other product-form models, we can say first that SPNs with signals generalise G-networks with negative customers, triggers and catastrophes [14,16,15,10]. Moreover, they subsume the product-form SPN of [8], without batch token movements. It is worthwhile noting that, differently from [31,8], we deal mainly with open models, since triggers may cause token destructions, leading to an empty network in the long-term.…”