Re: Occurrences as Named Triples

On 06/01/2024 19:03, Niklas Lindström wrote:
> Given recent discussions (in emails and during the last Semantic TF
> meeting), I've adjusted my position, and come to some tentative
> conclusions.

The consolidated proposal can express RDFn requirements without 
introducing so much additional machinery.

> Thoughts?

-- "unasserted but described in a graph"

That means an RDF graph is no longer a set of triples.

The edge set has its own integrity rules and the rules have consequences.

-- Set of edges/occurrence/named triples
> solves the problem of mapping the name to the triple.

The problem is still there - it manifests in different ways.

Now there are RDF syntax documents which are illegal graphs because of 
contradictions are possible.

This is a SHOULD NOT / MUST NOT debate.

In the consoldiated-v1 design, one name SHOULD NOT be used for different 
triple occurrences.  Bad data modelling and usage happens in many ways 
so live with this one.  Warnings can be issues, or an impl can choose to 
make it a hard error (database abort). But the graph is a valid RDF graph.

Here in (3), it is MUST NOT. It must be enforced to be a compliant 
implementation.

A document in RDF syntax in which the name is reused has a logical 
contradiction and isn't an RDF Graph. No single triple is wrong.

That document might be billions of triples. It can not be split into 
smaller files - each smaller file could be a legal RDF graph.

-- What is the name token?

No URIs for names or there are now RDF graphs can't be merged yet each 
graph on its own is valid.

The names can't be blank nodes because the edge set names have a special 
property of "no inference" which would apply to the set of triples.

A new RDF term type is possible.

- SPARQL
> can still query over the inferred graph using SPARQL with entailment
> "off", and pick out the "raw data facts".

Current SPARQL makes sure that basic graph pattern matching is 
compatible with simple-entailment. This in-turn allows the entailment 
extensions.

https://www.w3.org/TR/sparql11-query/#BasicGraphPattern
https://www.w3.org/TR/sparql11-query/#sparqlBGPExtend

     Andy

Received on Thursday, 11 January 2024 10:17:57 UTC