Transition Invariants in Algebraic High-Level Nets

Transition invariants play an important role in the analysis of Petri nets. They determine cycles within a system. In this paper we present a categorical characterization of transition invariants in algebraic high-level (AHL) nets. Thus, when transforming or composing AHL nets using categorical structuring techniques , a suitable transformation or composition of their invariants becomes possible. We lift the categorical characterization of transition invariants from place/transition nets to AHL nets. We show that transition invariants are preserved by AHL net mor-phisms. Consequently, they are preserved under the horizontal structuring technique union, an important result for the development and analysis of complex software systems. A part of a medical information system case study serves as illustration throughout the paper.