For the benefit of people who haven't read up on Petri nets / reaction networks, could you say a few words about Lotka-Volterra, and why it is of interest? Do you come across it in your work?
Also, what specific classes of questions are well addressed through simulation. This is a wide-net question, which covers both stochastic and deterministic nets. One clear example is finding equilibrium states. What else?
I'm looking for some case studies which could be explained to developers, as motivating examples for developing simulation software for Petri nets.