On the expressive power of Petri nets with transfer arcs vs. Petri nets with reset arcs

In this paper, we revisit the conjecture of [1], stating that ε-free Petri nets with transfer arcs are strictly more expressive than ε-free Petri nets with reset arcs. In [1], an ε-free Petri net with transfer arcs is provided, whose language is conjectured not to be recognizable by any ε-free Petri net with reset arcs. We show that this latter conjecture is flawed, by exhibiting an ε-free Petri net with reset arcs that accepts the same language. We also provide a new ε-free Petri net with transfer arcs, for which we conjecture too that it recognizes a language that is not definable by ε-free Petri nets with reset arcs.