On the Topological Complexity of omega-Languages of Non-Deterministic Petri Nets

Abstract: We show that there are $\Sigma_3<sup>0$-complete languages of infinite words accepted by non-deterministic Petri nets with B\"uchi acceptance condition, or equivalently by B\"uchi blind counter automata. This shows that omega-languages accepted by non-deterministic Petri nets are topologically more complex than those accepted by deterministic Petri nets.