Motivation. We wrote a great application for ActiveMath, called iCMap, which visualizes the structures of a mathematical domain and helps students to understand an recreate those structures. This tool is interactive and provides verification as well a suggestion mechanism. One of the key implementation problems in this tool is the lack of seperation between data (queries) and logic. Because iCMap requires inference mechanism to compute transitivities or fault-tolerances for verification, all those inferences are implemented in Java making heavy use of the MBase. This approach has several problems:

• MBase interface does no inferencing. Hence, it does not calculate the transitive closure for a learning item. iCMap computes that itself and requires for this action resources. Consequently, for one query, iCMap needs to contact the MBase several times. A reduction to one query with one result set as response is wished.
• Because inferencing is inside iCMap Java methods, adding new queries is not easy and requires a rebuild and deployment of the application.
• Queries are not reusable as they are embedded in iCMap. They are to some extent “cryptified”, i.e., you have to go through the code and understand it. A standard query language would solve the problem.

Solution. To overcome those deficiencies, I suggest to implement in addition to MBase a RDF Store for OMDoc learning object’s metadata information. This store will be optimized for RDF models, will include a reasoner for OWL (Lite/DL), and accept SPARQL queries. The component can run as a web-service and will be therefore reusable for other applications. Possible technologies for the implementation are Sesame or Jena.