A theory of alternative designs for biochemical control systems.

: Any theory of alternative designs must include (a) an appropriate language for describing alternatives, (b) methods of analysis for relating system behavior to changes in design elements, and (c) methods for critically comparing the behavior of alternatives. Over the past two decades we have been reasonably successful in developing a theory of alternative designs that meets these basic requirements. The language for describing alternatives is provided by the S-system of differential equations discussed elsewhere in this volume. The methods of analysis consist of adaptations of conventional methods from control theory and newly developed algorithms specific for S-systems. The methods for making critical comparisons perhaps are less familiar and will be treated in some detail. Several applications of this theory to alternative designs for biochemical control are reviewed.