  The paper presents an explicit state-based modeling approach aimed at
modeling Systems of Systems behavior. The approach allows to specify and verify
incrementally safety and liveness rules without using model checking
techniques. The state-based approach allows moreover to use the system behavior
directly as an interface, greatly improving the effectiveness of the recursive
composition needed when assembling Systems of Systems. Such systems are, at the
same time, both parts and wholes, thus giving a formal characterization to the
notion of Holon.
