An Improved Construction of Petri Net Unfoldings

Petri nets are a well-known model language for concurrent systems. The unfolding of a Petri net is an acyclic net bisimilar to the original one. Because it is acyclic, it admits simpler decision problems though it is in general larger than the net. In this paper, we revisit the problem of efficiently constructing an unfolding. We propose a new method that avoids computing the concurrency relation and therefore uses less memory than some other methods but still represents a good time-space tradeoff. We implemented the approach and report on experiments.