modelformal-languagesformal-methodspetri-net

What will be the number of reachable states if Petri-Net model states are in loop


If i have a Petri-net Model of 8 Places and 8 Transactions.There is not any dead state in this model because the token is in loop and going through all 8 places in first loop. In second and remaining loops it will go through 6 places because the token will come to Place3 when T5 is executed. Here i want to know what will be the number of reachable states. Is Reachable states will infinite (because of the loop) or what ?enter image description here


Solution

  • It's a little hard to answer without seeing the exact net, but assuming it's a simple loop with one token, then there are four states -- distinct labeling of the places with tokens -- that repeat infinitely.

    Update

    Aha! That's a whole 'nother kettle of fish. Olay, so hand-simulate it. I did it by putting one finger on each token and following them. I'm going to name the places p_0 through P_7 by taking P_0 at top left and P_7 at bottom right, so the left column is P_0, P_1, P_2, the middle is P_3, P_4, the right P_5, P_6, P_7. So, we start with the labeled places as {P_0,P_7}.

    Start:

    This is a nice slide deck on Petri nets. http://www.labri.fr/perso/anca/FDS/Pn-ESTII.pdf