d3web-Core is main platform API (application programing interface) for the development of knowledge-based applications. The platform is available as a collection of Java libraries providing a sophisticated plugin architecture. A number of components is already included in d3web-Core: * General representation and persistence of terminological knowledge to represent question (inputs) and solutions (outputs). * Reasoning engines and persistence for strong problem-solving methods including ** Decision trees ** Scoring rules ** Temporal rules ** DiaFlux models (flowchart knowledge) ** Set-covering models (abductive knowledge) ** Scoring tables