- From: Olaf Hartig <olaf.hartig@liu.se>
- Date: Sun, 1 Sep 2019 18:22:53 +0000
- To: "public-rdf-star@w3.org" <public-rdf-star@w3.org>
- CC: Kingsley Idehen <kidehen@openlinksw.com>
Kingsley, On fredag 30 augusti 2019 kl. 15:50:48 CEST Kingsley Idehen wrote: > On 8/30/19 3:12 PM, Olaf Hartig wrote: > > On fredag 30 augusti 2019 kl. 12:13:27 CEST Kingsley Idehen wrote: > [...] > >> Here's a fixed version of my example. I've rebased identifiers for Alice > >> and Bob using an indexical > >> <https://www.lexico.com/en/definition/indexical#this> relative to > >> document (context provider) (as per my very first example). > >> > >> ## 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 : <#> . > >> > >> <> a foaf:Document . > >> <> foaf:name "Document about Alice"@en . > >> <> foaf:primaryTopic :Alice . > >> > >> :Alice rdf:type foaf:Person . > >> :Alice foaf:name "Alice" . > >> : > >> :Bob rdf:type foaf:Person . > >> :Bob foaf:name "Bob" . > >> :Bob foaf:age "23"^^xsd:integer . > >> > >> # Context clarity regarding :claims relation > >> > >> :claims a rdf:Property . > >> :claims rdfs:domain foaf:Person . > >> :claims rdfs:range rdf:Statement . > >> > >> # Olaf would like the following to as syntax-sugar (*rather than change > >> to > >> existing RDF semantics*): # :Alice :claims << :Bob foaf:age > >> "23"^^xsd:integer >> . > >> # for what follows > >> > >> :Alice :claims [ a rdf:Statement; > >> : > >> rdf:subject :Bob ; > >> rdf:predicate foaf:age ; > >> rdf:object "23"^^xsd:integer > >> > >> ] . > >> > >> ## Turtle End ## > > > > Yes. > > > > Now, notice that the :claims property you are using here is different from > > the :claims property as used in your earlier examples. That is, your > > earlier examples used the :claims property as if it was defined as follows: > > > > :claims a rdf:Property . > > :claims rdfs:domain foaf:Person . > > :claims rdfs:range foaf:Person . > > > > -Olaf > > We can't simply assume that :claim denotes an rdf:Property that has > range rdf:Statement. Basically, to speak about any rdf:Property instance > we have to be clear about its rdfs:domain and rdfs:range for appropriate > context. I agree. > [...] > As I see it, the issue we are debating is primarily about reification > and syntax sugar for articulation convenience i.e., does this actually > constitute what's denoted as RDF* Semantics On one hand, RDF* may be used as syntax sugar. On the other hand, it also is an abstract data model. In the context of the latter, we may define a model- theoretic semantics for RDF* graphs (similar to the definition of the semantics of RDF graphs). This semantics is what I mean by "RDF* semantics" and my draft of it can be found at: http://htmlpreview.github.io/?https://github.com/w3c/EasierRDF/blob/master/ RDFstar/RDFstarSemantics.html > (for which I am currently unconvinced, bearing in mind what exists > regarding the roles of RDF [DDL] and SPARQL [DML] which offers > Named Graphs as a solution). Using (single-triple) Named Graphs is an alternative option for representing and querying metadata about individual triples. The downside of this option, however, is that this option makes it difficult to also represent and query metadata about specific sets of triples (graphs) at the same time (i.e., within the same dataset). Olaf
Received on Sunday, 1 September 2019 18:23:23 UTC