Re: LPG many-to-many

> On Aug 23, 2024, at 10:51 PM, Franconi Enrico <franconi@inf.unibz.it> wrote:
> 
> On 24 Aug 2024, at 01:48, Gregory Williams <greg@evilfunhouse.com> wrote:
> 
>> LPGs do not “handle reflexive relations.” I think this is just like many RDF systems that do not support reflexive reasoning – <Alice marriedTo Bob> and <Bob marriedTo Alice> would be treated as two triples/edges. Nothing more.
> 
> This is not true. In the GQL standard there are “undirected edges”, which capture exactly this case.
> (minor comment: this is called symmetric, not reflexive).

That’s a good point. I think we are talking about two different things, though. I (perhaps mistakenly) thought the question was about how LPG would treat two triples that used a predicate/property that was known to be reflexive due to some schema information (which in the RDF world would inform reasoning behavior). If it was instead about using LPG expressivity which is beyond what RDF provides (and is somewhat orthogonal to ’statements about statements’), then I agree that undirected edges could be used here. BUT, since one of the questions Thomas asked was about how many marriages would be counted due to these statements, there’s a bit of a gap between either of our answers and the question since the edges in our LPG examples aren’t typed as marriages – they’re just edges. To your point, though, the use of an undirected edge could certainly change the answer to the slightly different question, “how many :marriedTo edges are there?”.

thanks,
.greg

Received on Saturday, 24 August 2024 16:35:08 UTC