Formal verification coverage: computing the coverage gap between temporal specifications

Abstract

Existing methods for formal verification coverage compare a given specification with a given implementation, and evaluate the coverage gap in terms of quantitative metrics. We consider a new problem, namely to compare two formal temporal specifications and to find a set of additional temporal properties that close the coverage gap between the two specifications. In this paper we present: (1) the problem definition and motivation, (2) a methodology for computing the coverage gap between specifications, and (3) a methodology for representing the coverage gap as a collection of temporal properties that preserve the syntactic structure of the target specification.