I am learning something about P/T petri nets from the book from Wolfgang-Reisig authors and on the seventh chapter's end there is an exercise I can not really work out.
It asks me to construct initial marking such that the following marked graph is live and safe. Note that yellow highlighted place is for the latter part of the question and does not bear any other special significance.
Right after this exercise, there is following task, which asks me to do this: Show that the initial marking of each marked graph can be modified such that live and safe marked graph is obtained.
Based on that, I assume that it must be possible for any marked graph to have initial marking such that the graph is live and safe. But still I was not able to construct such initial marking. Is there an algorithmic approach to the task? And if I were to remove the highlighted part of the marked graph, would it still be possible to construct such graph?