•Abstract
syntax
•Semantics
•Layering
definitions: e.g., Datalog Horn layer
•Concrete
syntax:
–Markup
syntax in XML
–RDF
(e.g., RDF/XML)
–Human-readable
presentation (non-XML) syntax
•UML/MOF
metamodel
•Some light
ontology about rudimentary rule management, incorporated into the above
–E.g., to enable representing provenance,
or expressive restrictions met, about a
particular rulebase