Composition/décomposition de réseaux de petri et de leurs graphes de couverture

— In this paper, we study composition and décomposition of Pétri nets via a common set of places or transitions. We prove that some properties are preserved by these techniques\ and some other ones can be obtained by the composition of the covering graphs. We propose some algorithms to décompose a net according to the properties that must be verified. We present an algorithm to compose minimal covering graphs, less expensive than a straightforward construction, concerning as well time as space.