Hierarchical Design Based on a Calculus of Nets

We present an algebraic approach to hierarchical design of integrated circuits. This approach is based on a "calculus of nets" which includes topological as well as behavioural aspects of integrated circuits. We have developed a hierarchical design system called CADIC which is build around this calculus in much the same way as e.g. Algol is build around numerics. An example for the design of a family of fast adders will demonstrate the power of this calculus. Finally we will give a summary outline on the structure of procedures which automatically transform the design into lower design levels.