Re: RDF* semantics

On 8/30/19 8:04 AM, Olaf Hartig wrote:
> Thomas,
>
> Just to add to Pierre-Antoine's response, perhaps it is necessary to
> emphasize that you should not get hung up on the fact that the example
> uses blank nodes. That's also secondary to the point I am trying to
> make. So, instead of using blank nodes, we may present the example data
> with two IRIs that denote Alice and Bob, respectively. For instance, if
> we replace _:b1 by IRI http://example.org/Alice and _:b2 by IRI
> http://example.org/Bob, then we have the following snippet of Turtle
> (prefix declarations omitted).
>
> <http://example.org/Alice>  rdf:type  foaf:Person .
> <http://example.org/Alice>  foaf:name  "Alice" .
> <http://example.org/Alice>  :claims  <http://example.org/Bob> .
> <http://example.org/Bob>  rdf:type  foaf:Person .
> <http://example.org/Bob>  foaf:name  "Bob" .
> <http://example.org/Bob>  foaf:age "23"^^xsd:integer .
>
> Perhaps now it becomes more apparent that, according to this data,
> person Alice claims the person Bob (who is of age 23). This is different
> than saying that person Alice makes the following claim: the thing
> denoted by IRI is a person named Bob who is of age 23.
>
> Best,
> Olaf


Hi Olaf,

I think your example above needs a little more context i.e., clarity of
the relationship type (i.e., :claims in this example) that connects
Alice and Bob. Here's how I would add the missing context using
RDF-Turtle notation.


Fundamentally, the claims (in the form of a collection of RDF
statements) made by Alice are conveyed in a Document.

## Turtle Start ##

@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
@prefix foaf: <http://xmlns.com/foaf/0.1/> .
@prefix Alice: <http://example.org/Alice#>.
@prefix Bob: <http://example.org/Bob#> .
@prefix : <#> .

<> a foaf:Document .
<> foaf:name "Document about Alice"@en .
<> foaf:primaryTopic Alice: . 
 

Alice:  rdf:type  foaf:Person .
Alice:  foaf:name  "Alice" .

# Alice:  :claims  <http://example.org/Bob> .

Bob:  rdf:type  foaf:Person .
Bob:  foaf:name  "Bob" .
Bob:  foaf:age "23"^^xsd:integer .

# Context clarity regarding :describes relation

:describes a rdf:Property .
:describes rdfs:domain foaf:Person . 
:describes rdfs:range rdf:Statement . 

Alice:  :describes  [ a rdf:Statement;
                        rdf:subject Bob: ;
                        rdf:predicate foaf:age ;
                        rdf:object "23"^^xsd:integer 
                    ] . 

## Turtle End ##

Links:

[1] https://kingsley.idehen.net/public_home/kidehen/Public/Linked%20Data%20Documents/Tutorials/label-property-graph-stuff/alice-describes-bob.txt -- Text document that nanotation-friendly (i.e., processed by our OSDS Browser Extension for visualization effect)

[2] https://kingsley.idehen.net/public_home/kidehen/Public/Linked%20Data%20Documents/Tutorials/label-property-graph-stuff/alice-describes-bob.ttl -- RDF-Turtle Document 

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