Re: The way forward

I think I can comment with some insight into the original intent of RDR, RDF*, etc.  The intent was a mechanism for statement level metadata.  With this mechanism, it is possible to build up edge properties and a variety of other constructions.  Today, LPG interoperability is certainly a major use case, but that was less true back in 2000s when I was doing talks on Reification Done Right (RDR).  The gap has always been there with the semantic web.

Some people have asked why same identifier for multiple different triples is a problem.  It's a problem because it is simply not responsive to these original motivating use cases (edge properties, statements about a single statement to supposed security, provenance, etc.).  Because there can be multiple statements grouped under the same identifier, this can not reliably be used to construct edge properties, etc.

I think it is best to call the current proposal Statements about Graphs.  That is an accurate description of what it achieves.

However, Statements about Graphs does not support use cases relying on the ability to make assertions about single statements.  Yes, of course a Graph can contain a single statement and under this case things reduce to the same thing.  But any applications or platforms that want to build up mechanisms such as edge properties can not build upon that special case unless it is protected, for example, by a well-formedness constraint, by a profile, etc.

Thus, going forward without something which clearly and without ambiguity supports "Statements about Statements" (which has always meant statements about a specific Statement, not about a Graph) fails to support the key motivating use cases behind Reification Done Right, behind RDF*, and behind the Charter of this working group.

I can see a compromise emerging with anything which allows that necessary and sufficient restriction.  But without such a restriction, the output of this WG would fail to address the central motivating use cases that got all of this rolling.

And this is not about efficiency.  Statements about Graphs is not the same as Statements about Statements.  The former is one or more statements about one or more statements.  The latter is one or more statements about a single statement.  That single statement restriction is necessary for this mechanism.  Statements about Graphs is different.  It's not more general.  It's different.


From: Lassila, Ora
Sent: Wednesday, April 24, 2024 5:37:13 PM
Cc: Thompson, Bryan
Subject: The way forward

[My apologies that this comes at the last moment before tomorrow’s meeting.]

We have had long discussions within the Neptune team about the ongoing debate in the WG. We want to find an amicable, consensus-based way forward. Obviously the support within the WG for the multi-triple reifier proposal is strong, and we understand that many WG members may not be willing to live with the single-triple reifier approach. That said, we also believe that we (Neptune and our OneGraph project) need to be true to our vision of the future of “graph interoperability”.

Thus, we would like to bring back the idea of profiles: one for the multi-triple reifier support, another for the single-triple option. This would allow implementors some leeway, and would ultimately let the graph marketplace choose. People already make choices about what technologies they use, sometimes based on the level of support different technology vendors offer. Bottom line: we do not want to block progress in the WG, and this would let us move towards finishing the specifications. I think it is better that we get the largest possible number of implementors building RDF 1.2 -compliant products, rather than some companies “opting out”.


Dr. Ora Lassila
Principal Technologist, Amazon Neptune

Received on Thursday, 25 April 2024 14:48:35 UTC