The way in which a frequently evolving product is configured is a key issue in making predictions on its behavior in specific environments, with potentially major implications in taxing industries. Product Definition Systems (including Decision Support Systems) are proposed to support a dynamic alignment with fast changing contexts (outer environments) of products innovation (inner environments) conceptualized as complex systems. The alignment difficulty is theoretical (undecidability) and not solely practical to support products interchangeability (NP-complete problem). In changing environments new product versions have to be defined and named with corresponding properties or knowledge extensions. Our approach through syntax and semantics clears how such (product innovation) systems and knowledge extension are related to change the universe of possibles including problem space and solution space. It is an important topic for research on knowledge economy and Product Definition System.
