Persistence is a strong, global, behavioural property of a Petri net, meaning that no activity can disable a different activity. Persistent permutability is a weaker property, pertaining to individual interleavings of a Petri net and stating that a non-persistent sequence can be permuted into a persistent one. We identify Petri net classes for which persistent permutability already suffices to imply overall persistence. These classes generalise free-choice nets and are related to Petri's concept of ``confusion'', while they are distinguished from each other by diverse restrictions on the choice structure of a net. We prove Ochmanski's conjecture to be correct for these classes.

翻译：持续性是Petri网的一个强全局行为性质，指没有任何活动能禁用另一活动。持续可置换性是一个较弱的性质，涉及Petri网中单个交错序列，表明非持续序列可通过置换转化为持续序列。我们识别了若干Petri网类，在这些类中持续可置换性足以蕴含整体持续性。这些类推广了自由选择网，并与Petri的"混淆"概念相关，同时它们通过对网选择结构的不同限制相互区分。我们证明了Ochmanski猜想在这些类中成立。