In: Fundamenta Informaticae, Vol. 11, No. 2, pages 171-194. 1988.
Abstract: In the paper a characterization of concurrent systems as algebras of a special kind is given. The algebras are defined by semi-equations in the first order language --- In the Petri net approach processes are some system morphisms; in the approach of Winkowski the notion of system is not needed. The approach presented in this papaper is a sense ``between'' the above ideas; it comprises a new concept of system morphism.