// Author: schuessf@informatik.uni-freiburg.de
// Date: 2023-05-10

PetriNet net = (
  alphabet = {a b bb c cc d e f},
  places = {p1 p2 p3 p4},
  transitions = {
    ({p1} b {p2 p3}) 
    ({p2} c {p4}) 
    ({p3} d {p3}) 
    ({p4} e {p2}) 
  },
  initialMarking = {p1},
  acceptingPlaces = {p3 p4}
);

assert(!buchiIsEmpty(net));