“…The concept was originally presented in Carl Adam Petri's dissertation (Petri, 1966), and their early development and applications are found in reports that date back to the 1970s. PN became popular in theoretical computer science (Jensen & Kristensen, 2009), biology (Koch, 2010;Koch et al, 2010;Wilkinson, 2011), especially to represent parallel or concurrent activities (Murata, 1989), stochastic mechanics (Baez & Biamonte, 2012;Haas, 2006;Marsan et al, 1994), and to describe reaction networks (Gilbert & Heiner, 2006;Herajy & Heiner, 2015). In the case of reaction networks, clearly treated in Herajy and Heiner (2015),there are specific rules for computation, which are implicit in the PN structure used that do not lead to correct mass and energy budget equations.…”