]> Super class of all SSWAP classes. SSWAP classes use recognizable patterns to express required and optional predicates. Basically, cardinality constraints on predicates within an owl:equivalentClass block describe required predicates, while the same inside rdfs:subClassOf blocks describe optional predicates. This model can be used by any service in its own Resource Description Graph to express required and optional arguments. See sswap:Subject, since this is the class that resource providers will use to express the input data types of their services. Conditions for inclusion in the class are weak: in accordance with the open world assumption, any individual can be a member of this class except those known to belong to a class disjoint from every SSWAP subclass.