Hybrid Systems are models of interacting digital and continuous devices wit
h applications in the control of aircraft, computers, or modern cars for in
stance. Concurrently, Fluid Stochastic Petri Nets (FSPNs) have been introdu
ced as an extension of stochastic Petri nets to model physical systems that
contain continuous fluid quantities controlled by discrete logic, as well
as a means to deal with the possible state explosion of discrete models. Of
course, an FSPN is by definition a hybrid system but in this paper, we com
pare a general hybrid systems formalism with FSPN formalism. The conclusion
of this paper, suplemented by some examples, is that fluid stochastic Petr
i nets and hybrid system formalism can be converted from one to the other.
Although there is a price to pay for such a conversion, the conversion can
transfer the solution methods from one to the other and thus help the devel
opment of both formalisms.