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：持久性是Petri网的一种强全局行为属性，意味着任何活动均无法禁用其他活动。持久可置换性则是一种较弱的性质，它关注Petri网中单个交错序列，指出非持久序列可通过置换转化为持久序列。本文识别了若干Petri网类别，对于这些类别而言，持久可置换性已足以推导出整体持久性。这些类别推广了自由选择网，并与Petri提出的“混淆”概念相关，同时通过各自对网络选择结构的不同限制相互区分。我们证明了Ochmanski猜想在这些类别中成立。