Re: Against the notion of reification well-formed graph (i.e., atomicity)

(note that I am referring to the sugar proposal at https://github.com/w3c/rdf-star-wg/blob/main/docs/sugar-proposal.md)

In this message I want to argue against the notion of reification well-formed graph (i.e., atomicity).

Adding atomicity violates a necessary aspect of the proposal (as written by pfps):
"There is no intended meaning of the new concrete syntax beyond what it expands to".

According to atomicity:

(1)
<<:a | :s1 :p1 :o1>> :s :o .
<<:b | :s2 :p2 :o2>> :s :o .
:s1 :same-as :s2 .
:p1 :same-as :p2 .
:o1 :same-as :o2 .
should entail
:a :same-as :b .

Atomicity adds an intended meaning: it assumes that the same triple has systematically the same identifier, and therefore (1) should be a valid entailment.
If you don’t like entailment (1), then you contradict the intention of atomicity, UNLESS you assume full opacity.

(2)
<<:a | :s1 :p1 :o1>> :s :o .
<<:b | :s2 :p2 :o2>> :s :o .
:a :same-as :b .
should entail
:s1 :same-as :s2 .
:p1 :same-as :p2 .
:o1 :same-as :o2 .

Atomicity adds an intended meaning: it assumes that a resource identifies at most one triple.
If you don’t like entailment (2), then you contradict the intention of atomicity, UNLESS you assume full opacity.

So, (1) and (2) show that EITHER you assume full opacity (and therefore you are assuming an intended meaning), OR you accept the above entailments (and therefore you are assuming an intended meaning).
Note also that entailments like the above make the life of SPARQL BGP matching more complex.

I also understand that most (if not all) use cases assume transparency.

(3)
Atomicity would disallow writing typical reification statements like:
<< :w1 | :bill-clinton :related-to :hillary-rodham >> :starts 1975 .
<< :w1 | :42nd-potus :husband :1st-female-NY-senator >> :starts 1975 .


cheers
—e.