The S3DB application relies on an underlying Core Model, documented in PLoS ONE (2008) 3(8): e2946, that formalizes a common representation format which can be interpreted across S3DB Deployments. Although the S3DB application has some parallels with RDF triple stores, it constrains the triples that can be declared to instances of entities of the Core Model. The Core Model therefore formalizes these entities and the relationships between them. We use RDFS (RDF Schema) sparsely where an small degree of inference can save the need to specify all the triples. 

Figure 1. Core model developed for S3DB (supported by version 3.0 onwards). This diagram can be read starting from the most fundamental data unit, the Attribute-Value pair (filled hexagonal and square symbols). Each element of the pair is object of two distinct triples, one describing the domain of discourse, the Rules, and the other made of Statements where that domain is populated to instantiate relationships between entities. The latter includes the actual Values. Surrounding these two nuclear collection of triples, is the resolution of Collection and its instantiation as Item that define the relationship between the individual elements of Rules and Statements. The resulting structure is then organized in Projects in such a way that the domain of discourse can nevertheless be shared with other Projects, in the same or in a distinct deployment of S3DB. Finally, a propagation of user permissions (dashed line) is defined such that the distribution of the data structures can be traced. See text for a more detailed description. This is a refined version of the Core Model as described in  PLoS ONE (2008) 3(8): e2946.

The relationship between S3DB entities is defined by the following statements:

s3db:UD a rdf:Property;

Given this very specific detail of the S3DB Core Model, from the triple:

One could derive three more triples: