Document ODIS metadata graph fundamentals

[pbuttigieg]

The emerging CDIF Discovery guidance describes implementation of discovery-focused (meta)data graphs using JSON-LD and schema.org. Due to the co-development / parallel development of ODIS-Arch and CDIF during WorldFAIR (see D11.1, 11.2, 11.3), there's high overlap, but as described in Cross-Domain-Interoperability-Framework/Discovery#13 and D11.3, differences that may prevent full alignment.

Task: Document the ODIS-Arch approach to implementing JSON-LD/schema.org, with specific clarity on:

• the handling of reference nodes in JSON-LD using schema.org semantics
• the role of identifiers other than reference node @ids
• the creation of metadata about metadata documents.

The objecctive is that this ODIS guidance forms a subsection in the CDIF Discovery guidance, as an alternative to the currently documented options. There are multiple reasons for this alternative, including the generation of lean graphs without superfluous content, operating within the same level of semantic and logical abstraction, and consistency with the schema.org and JSON-LD specifications.