General observation structures for Petri nets

Observation structures usually considered for Petri nets assume that the firing of transitions may be observed through static labels and that the marking of some places may be measurable. These observation structures are rather limited and we consider in this paper more general ones, correspondingly defining two new classes of nets: labeled Petri nets with outputs and adaptive labeled Petri nets. Several examples of nets in these classes are considered. Furthermore we also show the possibility to convert a labeled Petri net into an adaptive Petri net or a labeled Petri net.