I'm trying to build bridges between mathematics and practical subjects like information technology and engineering. A Petri nets (PNs) are a graphical and mathematical tool that are used for describing and studying information processing systems that are characterized as being concurrent, asynchronous, distributed, parallel, non-deterministic and/or stochastic. As a graphical tool, Petri nets can be used as a visual-communication aid similar to flow charts, block diagrams and networks. Tokens are used in these nets to simulate the dynamic and concurrent states of systems. As a mathematical tool, it is possible to set up state equations, algebraic equations and other mathematical models governing the behavior of systems. Since Petri nets are a formal methods' designing and modeling technique, so they are used to model complex systems as mathematical entities. By building a mathematically rigorous model of a complex system, it is possible to verify the system's properties in a more thorough fashion than empirical testing.