In: Theoretical Computer Science Vol. 96, pages 285-304. 1992.
Abstract: We define algebraic systems called concurrent regular expressions which provide a modular description of languages of Petri nets. Concurrent regular expressions are extension of regular expressions with four operators - interleaving, interleaving closure, synchronous composoiton and renaming. This alternative characterization of Petri nets languages gives us a flexible way of specifiying concurrent systems. Concurrent regular expressions are modular and, hence, easier to use for specification. The proof of equivalence also provides a natural decomposition method for Petri nets.