Slicing techniques for verification re-use

In this paper we discuss which properties of a formally verified component are preserved when the component is changed due to an adaption to a new use. More specifically, we will investigate when a temporal logic property of an Object-Z class is preserved under a modification or extension of the class with new features. To this end, we use the slicing technique from program analysis which provides us with a representation of the dependencies within the class in the form of a program dependence graph. This graph can be used to determine the effect of a change to the class's behaviour and thus to the validity of a temporal logic formula.