An application of a four-way framework for validating a specification: Animating an Object-Z specification using Prolog

A great deal of the benefits of formal methods stems from their ability to rigorously and precisely specify, at an initial stage, the requirements of the system being developed. Errors in requirements are detected and eliminated earlier and important properties of the system can be formally established thereby, allowing the analysis of the behaviour of the system before the design. These benefits come at two significant prices: firstly, due to its rigour and the level of details, the specification process is a difficult and costly exercise. Secondarily, a formal specification becomes exploitable when it is carefully validated. The search for appropriate validation guidelines, frameworks, methods and techniques is a continuous endeavour of researchers especially with techniques such as Object-Z for which tool support are still very scarce. This paper follows a 4-way framework for validating a specification, to validate an Object-Z specification. During the validation, a mechanism is proposed to translate the specification into Prolog facilitating its animation. A case study is used to illustrate the approach. Keywords—Formal Specification, Specification validation, 4way framework, Object-Z, Animation, Prolog.