Pomset automata are an operational model of weak bi-Kleene algebra, which describes programs that can fork an execution into parallel threads, upon completion of which execution can join to resume as a single thread. We characterize a fragment of pomset automata that admits a decision procedure for language equivalence. Furthermore, we prove that this fragment corresponds precisely to series-rational expressions, i.e., rational expressions with an additional operator for bounded parallelism. As a consequence, we obtain a new proof that equivalence of series-rational expressions is decidable.

@article{paperbot1285,
  title = {Equivalence checking for weak bi-Kleene algebra},
  author = {Tobias Kappé and Paul Brunet and Bas Luttik and Alexandra Silva and Fabio Zanasi},
  journal = {Logical Methods in Computer Science},
  volume = {Volume 17, Issue 3},
  year = {2021},
  doi = {10.46298/lmcs-17(3:19)2021}
}