Consider the following Petri net with the initial state as shown in the figure. The number on the arrows indicates how many tokens have to be consumed or will be produced. Assume we start from initial state for all the question.

(1) Is it possible for deadlock to occur? If yes, state the sequence of transaction that will lead to deadlock.

(2) State the shortest firing sequence to put 4 tokens in p3, and no other places contain any tokens.

(3) State the shortest firing sequence to put 4 tokens in p2, no other places contain any tokens.

(4) What is the minimum number of transition needed before we can fire t2? Show your calculation.

p2 10 13 -11 p1 12 -15 10 3 2 2 p3