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characteristics of proposed semantics

From: Peter F. Patel-Schneider <pfpschneider@gmail.com>
Date: Fri, 12 Feb 2021 10:28:03 -0500
To: "public-rdf-star@w3.org" <public-rdf-star@w3.org>
Message-ID: <a71626b5-836f-b88a-5866-d8cf396819d1@gmail.com>
There appears to be five different semantics that have been recently proposed.

The proposals can be found in
1/ https://github.com/w3c/rdf-star/pull/81
2/ https://github.com/w3c/rdf-star/pull/88
3/ https://lists.w3.org/Archives/Public/public-rdf-star/2021Jan/0057.html
4/ https://lists.w3.org/Archives/Public/public-rdf-star/2021Jan/0059.html
and
5/ https://lists.w3.org/Archives/Public/public-rdf-star/2021Feb/0038.html

All proposals create RDF graphs and the semantics of RDF* is defined as a 
semantics for these RDF graphs.

The differences between them lie in four areas:
A) RDF* graphs as an abstract syntax
B) hidden vocabulary for RDF* reification
C) special datatype(s) for embedded triples
D) extended semantics for RDF* reification vocabulary

First, there is whether there is the notion of an RDF* graph. RDF* surface 
syntax can be expressed by parsing RDF* surface syntax into RDF* graphs and 
then transforming these RDF* graphs into RDF graphs.  Alternatively, RDF* 
surface syntax can be expressed by parsing surface syntax directly into RDF 
graphs.

Second, there is whether the vocabulary used to reify embedded triples is 
hidden or not.  If so, then RDF* embedded triples cannot be constructed by 
means other than embedded triple syntax.  If not, then regular RDF constructs 
(almost certainly reification) can be used to get the same effect as embedded 
triples.

Third, there is whether one or more special datatypes are needed for the 
subject, predicate, or object of embedded triples.

Fourth, there is whether the semantics of RDF* needs an extension of RDF 
semantics on the resultant RDF graphs (aside from the semantics of any new 
datatypes).

Here is a table of my understanding of how the proposals stand on the above 
differences.

             1/ P81    2/ P88    3/57    4/ 59    5/ 38

A) RDF* graphs        YES    YES    YES    YES    NO
B) hidden vocabulary    YES    YES    NO    NO    NO
C) special datatype(s)    YES    NO    YES    NO    NO
D) extended semantics    YES    NO    NO    NO    NO






peter
Received on Friday, 12 February 2021 15:28:17 UTC

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