A case study of constructing formal specifications using a stepwise data refinement approach

Abstract

Formal methods for developing computer systems improve the quality of documentation, making the documents precise for understanding. Formal methods are established based on mathematics; they usually require high cost for training and personal skills to use. For these reasons, there are still challenges when they are applied to business software systems development in industry. In this paper, we present an example to show that a stepwise data refinement approach can be used to facilitate the construction of formal specifications. We first discuss how data types and related objects for input and output are defined clearly, and then present how the declared types and variables are used to write operation specifications.