Class B requirements
q Relational types (transitive, reflexive, symmetric,…)
q Class as instance
q Ontology mapping (equivalent to)
q Ontology partitioning
q Complex datatypes
q Closed world assertions
q Tagging/ grouping
Class C
q Layering  (both similar to oil  and layering on rdfs)
q Effective decision procedures
q Commitment to portions of ontologies