Figure 2

The Canonical Graph. OWL DL definitions (not shown) of the fundamental SSWAP classes require all SSWAP compliant resources to express themselves within the framework of the five classes and six predicates as shown here. General practice is to create one file for the provider's description (2A), and one file for each semantic web service (2B). Ovals represent classes; blue ovals are SSWAP reserved classes, orange ovals are third-party classes; rounded-cornered rectangles represent instances (individuals); arrows represent predicates (properties). SSWAP uses the W3C sanctioned encoding of RDF/XML, but code snippets shown here and in the following figures is in the more compact N3 solely for readability. A note on N3: the word 'a' is shorthand for rdf:type and denotes instantiation. Multiple classes are specified serially in a statement with a comma (,) delimiter. A semicolon (;) means that the RDF subject of the assertion is the same as the subject of the preceding line, so the line lists only the predicate and object; blank nodes are represented by square brackets ([]) which allow a nesting of relationships. In some cases blank nodes are labeled explicitly using the prefix underscore-colon (_:) followed by the label.