Re: RDF-star vs Wikidata for modelling Richard Burton

On 09/12/2021 11:32, Pierre-Antoine Champin wrote:
> 
> On 09/12/2021 12:23, Andy Seaborne wrote:
>>
>>
>> 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.
> 
> The way I read Peter's question was : are there PG implementation in 
> which properties (I assume that's what you mean by "attributes") have 
> nodes as their value?

 >>>> where edges can only be related to values

I haven't found any serializations that put nodes or edge ids in the 
data model.

The serializations have values that are strings and numbers 
(JSON-centric). Nothing else.

Which formalizations have a type system for values?

     Andy

> 
>>
>>     Andy
>>
>>>
>>>> (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 12:50:23 UTC