Contents 1 Introduction 9 1.1 Current system description languages . . . . . . . . . . . . . . . . . 9 1.2 Formal function theory . . . . . . . . . . . . . . . . . . . . . . . . . 10 1.3 Interpretation of formal functions . . . . . . . . . . . . . . . . . . . . 11 1.4 Semantic functions . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 1.5 System semantics . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 1.6 Adirectional systems . . . . . . . . . . . . . . . . . . . . . . . . . . 14 1.7 Applications of system semantics . . . . . . . . . . . . . . . . . . . . 14 1.8 The ESPRIT project FORFUN . . . . . . . . . . . . . . . . . . . . . 14 1.9 The contents of this thesis . . . . . . . . . . . . . . . . . . . . . . . . 16 2 Mathematical background 17 2.1 Overview of mathematical notation used . . . . . . . . . . . . . . . . 18 2.2 Formal function theory . . . . . . . . . . . . . . . . . . . . . . . . . 18 2.3 Formal language theory . . . . . . . . . . . . . . . . . . . . .

In this paper, the design strategy for a circuit synthesis program is described. Unlike other synthesis programs, the program searches in an extremely large set of possible circuits (over 1,000,000 possible circuit configurations), and is not restricted to one device technology. It uses