A Theory of Mutations with Applications to Vacuity, Coverage, and Fault Tolerance

The quality of formal specifications and the circuits they are written for can be evaluated through checks such as vacuity and coverage. Both checks involve mutations to the specification or the circuit implementation. In this context, we study and prove properties of mutations to finite-state systems. Since faults can be viewed as mutations, our theory of mutations can also be used in a formal approach to fault injection. We demonstrate theoretically and with experimental results how relations and orders amongst mutations can be used to improve specifications and reason about coverage of fault tolerant circuits.