Re: "Multi-Edge Support in RDFn" slides

Although the word "denotes" is not used for this purpose in the RDF 1.1 
semantics, blank nodes definitely are mapped into resources similarly to IRIs. 
   It is just that the mapping uses an extra bit of semantic machinery:

 From the document:
Semantic condition for blank nodes
If E is an RDF graph then I(E) = true if [I+A](E) = true for some mapping A 
from the set of blank nodes in E to IR, otherwise I(E)= false.

So it takes this extra mapping, but blank nodes end up being mapped to 
resources.  One might want to say that this is not "denoting", but I don't see 
enough of a difference to support this restriction.  One could say that the 
denotation of an IRI is fixed in an interpretation but that the denotation of 
a blank node needs to combination of an interpretation and a blank node 
mapping to be fixed.


peter


On 12/16/22 13:24, Antoine Zimmermann wrote:
> Peter,
>
> Le 16/12/2022 à 17:21, Peter F. Patel-Schneider a écrit :
>>
>
> [skip]
>>
>>
>> Blank nodes absolutely do denote, just like global existential variables 
>> denote.   It is just that what they denote is in some sense less determined 
>> than what IRIs denote.
>
> You're using "denote" in a different way as I do, and it is not clear how. I 
> am using the standard RDF 1.1 Semantics (quote Section 4):
>
> "The words *denotes* and *refers to* are used interchangeably as synonyms 
> for the relationship between an IRI or literal and what it refers to in a 
> given interpretation, itself called the *denotation* or *referent*."
>
> Blank nodes do not denote in this sense.
>
> Regardless, the point is that when Pierre-Antoine says "bnodes mean the same 
> everywhere", it is odd, considering how the semantics of bnodes is defined.
>
>
> --AZ
>
>>
>> peter
>>
>>
>>
>> On 12/16/22 09:10, Antoine Zimmermann wrote:
>>>
>>>
>>> Le 16/12/2022 à 12:58, Pierre-Antoine Champin a écrit :
>>> >>   that means the same everywhere.
>>> > just like an IRI, a literal or a blank node means the same everywhere 
>>> (mind you, I'm talking about blank nodes, not blank node identifiers, who 
>>> have a local scope).
>>>
>>> What do you mean by "a blank node means the same everywhere"?
>>> Literals and IRIs denote the same thing everywhere, yes. Conversely, 
>>> bnodes do not denote anything. Bnodes only indicate the existence of 
>>> things, and what thing exists as indicated by a bnode depends on the RDF 
>>> graph being considered.
>>>
>>> It happens that the CG report interprets quoted triples as bnodes whose 
>>> identity depends on the RDF-star graph being considered. So if you 
>>> consider different RDF-star graphs containing the same quoted triple, the 
>>> quoted triple in the context of the first graph indicates the existence of 
>>> a different things than the quoted triple in context of the second graph.
>>>
>>> See https://w3c.github.io/rdf-star/cg-spec/editors_draft.html#mapping item 
>>> 2.2).
>>
>

Received on Sunday, 18 December 2022 18:55:12 UTC