Affiliations: Department of Mathematics, Tampere University of Technology, PO Box 553, FI-33101 Tampere, Finland. antti.valmari@tut.fi | Temasek Laboratories, National University of Singapore, Singapore. henri.hansen@gmail.com
Note: [] Address for correspondence: Department of Mathematics, Tampere University of Technology, PO Box 553, FI-33101 Tampere, Finland
Note: [] Formerly of Department of Software Systems, Tampere University of Technology
Abstract: Many algorithms for computing minimal coverability sets for Petri nets prune futures. That is, if a newmarking strictly covers an old one, then not just the old marking but also some subset of its successor markings is discarded from search. In this publication, a simpler algorithm that lacks future pruning is presented and proven correct. Its performance is compared with future pruning. It is demonstrated, using examples, that neither approach is systematically better than the other. However, the simple algorithm has some attractive features. It never needs to re-construct pruned parts of the minimal coverability set. It automatically gives most of the advantage of future pruning, if the minimal coverability set is constructed in depth-first or most tokens first order, and if so-called history merging is applied. Some implementation aspects of minimal coverability set construction are also discussed. Some measurements are given to demonstrate the effect of construction order and other implementation aspects.
