Stacking logic

RDF was designed to have other langauges like RDF schema and DAML stacked on top.

Problems arrise introducing semantics like QUOTE or NOT to naive processors.

Need to indicate changing semantics of higher-level languages.

Can be done by:

application-specific reification

       <rei:Triple><rei:predicate rdf:resource="#__c1" />
                   <rei:subject rdf:resource="#__s1" />
                   <rei:object rdf:resource="#__o1" /></rei:Triple>

(taken from an RDF query model)

non-RDF/XML syntax

N3, algae