Researching Of Basis Properties Of Petri Nets

Petri Nets is suitable for the description of asynchronous concurrent systems because, first of all, Petri net direct display system with the physical structure and status of resources distribution of the initial state. Secondly, Petri nets under the triggered rules will indirectly show the complicated dynamic behavior of the system. These two aspects interrelated and formed the integrated model which included the physical structure and the behavior mechanism. The model provides more information of systems and the analysis in theory is even more profound. The main behavior characters of Petri nets include: reachability,boundedness,liveness,reversibility,reachability,persistence,synchronic distance and fairness and so on.The Petri net model's main analysis methods relies on:reachable marking graph> the incidence matrixs and the equation of state, invariants and the analysis simplification rules.The Petri net take research model system's organizational structure and the dynamic behavior as goals, focuses between each change of state which as well as change relations possibly occurs in the system, easy to express the system change after the condition and the change has occurred in the system mode. The main difficulty of Petri nets application is the model state space complex question, it will increase along with the scale of actual system to assume the index growth. So, The algorithms about boundness Nets is always NP problems (always call The explosive in state space) . The researches of our countryand abroad are always pay more attention to the sub-classes on Petre Nets.They have given some well results, however, the results is short of application because of the particularity of sub-classes on Petri Nets. Our main works are basis on the general Nets.My research is mainly from the basic property of Petri nets. Using the constitutive analysis theory and the invariable technology thoroughly discuss the main behavior characteristic of Petri nets, and draw some new outcomes as follows:(1) The conflict is a basic phenomenon of Petri nets system. The conflicts make the tokens in places different and make the effect multiform. In this paper, the number of places and transitions in P/T system is finite. According to the defmiens of conflict in C/E system, finding out the static conflict vector that bring conflict and the corresponding cases confirm transitions and cases which bringing conflict. In this paper,arithmetic of finding out conflict is given.(2) The conflict in P/T system is more complex than in C/E system. In this paper, the number of places and transitions in P/T system is finite. Bringing the conception of conflict and incomplete conflict, giving the condition of conflict and incomplete conflict arising. Confirming the number of tokens in places in P/T system, when the conflict and incomplete conflict arise.(3) Fairness is the basic property of Petri nets. In this paper, using the incidence matrix of Petri nets solves the basic repeating vectors in the common Petri nets ,the vectors include minimum collections.the extension subnets are contructed by minimum collections. using the way that is gaven inliterature [1] .Finally, arithmetic is given.