Discovering petri nets including silent transitions. A repairing approach based on structural patterns

The paper presents a novel approach for discovering Petri nets (PN) that include silent transitions from logs of event sequences. We propose a repairing method that extends existing discovery techniques that do not deal with silent transitions; such techniques may yield substructures that involve deadlocks. Such substructures, called inconsistent (IS), are detected through a structural pattern. IS are rewritten by adding new transitions labelled with event symbols already assigned to transitions in IS; the rewritten model has no deadlocks. Afterwards, the PN with duplicated event labels is transformed into an equivalent model with silent transitions. The algorithms derived from the technique, which have polynomial-time complexity, have been implemented and tested on examples of diverse structures.