In: Information Processing Letters, Vol. 38, No. 2, pages 71-76. April 1991.
Abstract: The author shows that the problem of determining whether two transitions in a 1-bounded conflict-free Petri net can become enabled simultaneously is solvable in polynomial time, answering an open question posed by M. Tiusanen (see EATCS Bulletin, Vol. 36, p. 152--60, 1988).
Keywords: polynomial time algorithm (to decide) concurrency (of transitions for) 1-bounded conflict-free net.