Figure 5

Discovery Server Response Graph. The discovery server returns all graphs that satisfy the query. "Satisfaction" means that any resource returned in a response graph could be substituted as an individual of type sswap:Resource in the query graph while maintaining the truth of the assertions. Properties of semantic searching (Figure 4) mean that when querying for resources, discovered services are exactly those that are semantically guaranteed to operate on the input data (including those that accept more general classes) while returning the stipulated output data classes (including more specific classes). In the example here the client asked for all services that return data of type taxa:Taxa (Figure 4). The discovery server returned a service that returns data of type ncbiTaxa:TaxonomyRecord, which is a subclass (a specialization) of taxa:Taxa, thereby satisfying the request. Notice how this allows clients to find data and services based on the semantic and ontological relationships of services and data, even if neither the client nor any provider anticipated this usage. Full information is not returned in the response graph, but it available to clients by dereferencing resources to obtain their RDGs.