[UC] problems with CG report examples

I spent some time looking at the examples in the CG report 
(https://www.w3.org/2021/12/rdf-star.html).  Although these are not use cases 
it is possible to infer some characteristics of the usage from the examples. 
I didn't find the examples encouraging at all.  To my mind, almost all of them 
are poorly served by the semantics in the CG report.  The problems that I see 
include lack of generality, missing requirements to stand off from unique 
quoted triples, and lack of transparency.

Example 8 https://www.w3.org/2021/12/rdf-star.html#occurrences-example 
purports to show how to represent occurrences of triples in Turtle files,  But 
the solution is not a general one because it cannot represent triples that 
contain unlabeled blank nodes or collections in Turtle files such as
:joan foaf:knows [ foaf:name "Bob" ] .
or
:a :b ( "apple" "banana" ) .

Examples 5, 6, 7, 9, 10, 11, 12, and 13 use :statedBy, some in conjunction 
with :recorded.  They have the same problem as the seminal example in that if 
they do not stand off from the quoted triple then there is a problem of not 
being able to connect the :statedBy triple with correct other triples for the 
actual stating.  For example, :statedBy, particularly in conjunction with 
other attribution properties should stand off from a unique quoted triples so
<< :a :name "Alice" >> :statedBy :bob ; :on "2021-07-07"^^xsd:date .
<< :a :name "Alice" >> :statedBy :charlie ; :on "2021-07-08"^^xsd:date .
does not entail
<< :a :name "Alice" >> :statedBy :bob ; :on "2021-07-08"^^xsd:date .

Examples 1 through 4 and use the :accordingTo property.  Examples 36, 38, and 
39 use the :source property.  These are all better represented using a 
semantics that provides transparency.  So, for example (as indicated in the 
report)
dbr:Linköping dbo:populationTotal "104232"^^xsd::nonNegativeInteger
     {| :source <https://dbpedia.org/data/Linköping> |}.
when recognizing xsd:nonNegativeInteger should, but does not, entail
dbr:Linköping dbo:populationTotal "000104232"^^xsd::nonNegativeInteger
     {| :source <https://dbpedia.org/data/Linköping> |}.
But this is not just true for annotation syntax but is also true even when the 
triples are not asserted, because the inferred intended meaning is that 
:accordingTo and :source are not syntactic relationships and so equivalences 
true in the current graph should be taking into account.   Thus
<< :employee38 :height 5 >> :accordingTo :employee22 .
when recognizing xsd:integer should entail
<< :employee38 :height 05 >> :accordingTo :employee22 .

Examples 26, 27, 28, 30, 35, and 37 use :claims or :says or :reportedBy, which 
should either stand off from the actual quoted triple or be transparent, 
depending on what the intended meaning of their property is supposed to be.

peter

Received on Monday, 10 April 2023 17:28:16 UTC