π€ AI Summary
This paper addresses the (un)reachability verification problem between initial and error states in graph transformation systems specified by first-order nested conditions. Due to infinite state spaces, this problem is generally undecidable. To tackle it, we propose the first Counterexample-Guided Abstraction Refinement (CEGAR) framework tailored for general graph transformation systems with first-order nested condition constraints, integrating abstract interpretation, predicate abstraction, and graph transformation semantics into a terminating automated verification procedure. Our key contribution is a novel abstraction and refinement mechanism specifically designed for nested conditions, enabling precise unreachability proofs for complex, structured error states. We validate the effectiveness and practicality of our approach on multiple case studies. The method provides a new, generic pathway for formal verification of reactive systems governed by structural constraints.
π Abstract
This paper addresses the following verification task: Given a graph transformation system and a class of initial graphs, can we guarantee (non-)reachability of a given other class of graphs that characterizes bad or erroneous states? Both initial and bad states are characterized by nested conditions (having first-order expressive power). Such systems typically have an infinite state space, causing the problem to be undecidable. We use abstract interpretation to obtain a finite approximation of that state space, and employ counter-example guided abstraction refinement to iteratively obtain suitable predicates for automated verification. Although our primary application is the analysis of graph transformation systems, we state our result in the general setting of reactive systems.