Re: A few thoughts on RDF-star, Reification, and Labeled Property Graphs

My post was not an attempt to change the charter of the WG. It is the Neptune position on RDF-star. Our responsibility is to our customers; if we can also support RDF-star, so much better. Our reasoning was this:

1) a reifier reifies only one triple -- this moves RDF and LPG closer to one another (and makes RDF easier to explain to LPG users),
2) a reifier can reify multiple triples -- this moves RDF and LPG further away from one another (and makes RDF harder to explain -- I am referring, among other things, to my earlier comment about the confusion with named graphs).

Perfect alignment will not happen, of course, and I don't even see that desirable. But our proposed model enables us to have the same data and query it using any of the three query languages we support (SPARQL, openCypher, and Gremlin). It would allow us to support RDF-star in OneGraph. Also, an argument like "if you don't like the feature, don't use it" is not useful for technology vendors.

I really liked Felix's comparison to XML and SGML. It captures the spirit of our thinking.

What I would like to know is what those who see RDF as a serious business think about this.


´╗┐On 4/9/24, 3:14 PM, "Peter F. Patel-Schneider" < <>> wrote:

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I am truly confused by this reasoning.

As far as I know, the many-to-many capability would still allow for the simple
versions of edge properties, and would provide easy syntax for them. For example

:Dick :married :Liz {| :at :Montreal; :on "1964-03-15"^^xsd:date |}.
:Dick :married :Liz {| :at :Chobe; :on "1975-10-10"^^xsd:date |}.

would be valid syntax (and make sense, as opposed to the situation with the
earlier versions of RDF-star and with RDF*).

What the many-to-many capability does allow is the ability for edges to share
attached properties. Users who do not feel a need for this don't have to
avail themselves of the capability.

What should be done, of course, is to have separated querying of edge
properties work correctly for shared edge properties.

So what is the intolerable additional burden imposed by this capability?


PS: The above example demonstrates what I consider to be a major advantage of
RDF-star over Labelled Property Graphs. In Labelled Property Graphs, the
values of edge (or node) properties cannot be nodes. Whenever I consider
using Labelled Property Graphs for anything beyond trivial examples, I quickly
run into this deficiency.

On 4/9/24 14:02, Thompson, Bryan wrote:
> One would do this because the future relevance of RDF is at stake. It would
> be an extreme disservice to RDF to introduce a more conceptually complicated
> model of RDF Reification, and implicit grouping via the same identifier is a
> more conceptually complicated model. I have been involved in this via RDF-star
> since 2012 when I got Olaf interested in this problem and via "Reification
> Done Right" since 2008 and via other activities back to 1999 with a critique
> of the semantic web as being unable to handle uncertain and messy data, which
> is what we have in the real world. To my thinking, the conceptual
> difficulties of RDF reification have been a major reason why LPG had an
> opportunity in the graph standards market when we had solid detailed existing
> standards. LPG makes edge properties simple. And edge properties are a
> critical -- the number one critical -- use case for RDF Reification. There
> are to be certain other valuable use cases, but this is frankly table stakes
> for graph standards. RDF has a *lot* of other benefits, but it falls down on
> the handling of edge properties.
> To me, this is a question of basic relevance of RDF to the future. Getting
> this wrong will slam the door closed on RDF. Getting it right will make it
> possible to breath continued and new life into RDF.
> The issue for uptake and use by the broad graph community is not about having
> the "more capable model". What RDF needs is a model which provides a clear,
> effective and efficient semantics for edge properties and ... extending that
> ... for statements about statements.
> Bryane

Received on Tuesday, 9 April 2024 20:51:01 UTC