Model and program repair via SAT solving

We consider the subtractive model repair problem: given a finite Kripke structure M and a CTL formula η, determine if M contains a substructure M´ that satisfies η. Thus, M can be repaired to satisfy η by deleting states and/or transitions. We give a reduction to boolean satisfiability, and implement the repair method using this reduction. We also extend the basic repair method in three directions: (1) the use of abstraction, and (2) the repair of concurrent Kripke structures and concurrent programs, and (3) the repair of hierarchical Kripke structures. These last two extensions both avoid state-explosion.