Unified and Simplified Bisimulation

Paper in proceeding, 2024

Bisimulation is a powerful abstraction method, which can be used to perform model reduction, especially for modular transition systems. A unified formulation of strong, weak, stuttering, and branching bisimulation is presented. An ambiguity in branching bisimulation is also highlighted, and an equivalent reformulation is proposed where the ambiguity is avoided. A transitive and therefore an equivalence relation is also shown for the alternative formulation. A block transition based description that is more natural from a model reduction perspective is also shown to be equivalent to the original relation based bisimulations. All bisimulation formulations are based on general transition system models, which means that systems both including state and transition labels are handled in a unified way.