  Modelling, specifying and reasoning about complex systems requires to process
in an integrated fashion declarative and procedural aspects of the target
domain. The paper reports on an experiment conducted with a propositional
version of Logic Programming Petri Nets (LPPNs), a notation extending Petri
Nets with logic programming constructs. Two semantics are presented: a
denotational semantics that fully maps the notation to ASP via Event Calculus;
and a hybrid operational semantics that process separately the causal
mechanisms via Petri nets, and the constraints associated to objects and to
events via Answer Set Programming (ASP). These two alternative specifications
enable an empirical evaluation in terms of computational efficiency.
Experimental results show that the hybrid semantics is more efficient w.r.t.
sequences, whereas the two semantics follows the same behaviour w.r.t.
branchings (although the denotational one performs better in absolute terms).
