Re: RDF-star vs Wikidata for modelling Richard Burton

On 08/12/2021 08:07, Pierre-Antoine Champin wrote:
> On 07/12/2021 22:25, Peter Patel-Schneider wrote:
>> On Tue, 2021-12-07 at 14:52 +0100, Pierre-Antoine Champin wrote:
>>> In LPGs as well, there is a point were modelling marriages or pipes
>>> as edges will hit a wall. More specifically, if you want to relate
>>> them to other *nodes* of the graph (link a marriage to its location,
>>> link a pipe to its manufacturer), you also need to reifiy them as
>>> nodes.
>> I see some formulations of property graphs where edges can only be
>> related to values, but is that really the case for all property graphs?
> I have never seen an explicit definition of "Property Graphs" where this 
> was not the case (but I have not seen them all, of course).
> I also have the feeling that allowing nodes as property values would 
> pervert the idea of PGs, where the distinction between the internal 
> structure of nodes (properties) and relation with other nodes (edges) is 
> considered an important feature.

Looking at some of the JSON serializations at property graphs - they 
don't allow for edges to be nodes.

There are two styles:

* Nodes have integer ids, and edges are represented by start-end id 
pairs and a label.

* Edges have ids but the numbering of nodes and edges starts separately 
at 0 so there are different numbering spaces.

Both cases mean only attributes on edges.


>> (Well, if you think of Wikibase as a property graph formulation then
>> there is at least one counterexample.)
> It never occurred to me to put Wikibase in the "Property Graph" family. 
> I see some similarities, but also many differences. In particular, the 
> distinction I mentioned above (between "properties" and "edges" of a 
> node, in PG parlance) does not exist in Wikibase, where there all 
> represented as "statements" (except for labels and descriptions... but I 
> hope you see my point).
>    pa
>> peter

Received on Thursday, 9 December 2021 11:24:13 UTC