Re: [External] : Can a triple-term in an N-Triple 1.2 statement have "infinite" number of atomic terms?

An N-Triples 1.1 statement can have exactly three (atomic) terms. Going from that to supporting unbounded number of atomic terms in N-Triples 1.2 seems like a major extension.
I'd argue for N-Triples 1.2 to not allow nested triple-terms. (Of course, Turtle 1.2 will have no such restrictions and hence will be more human-friendly.)

So, if we go with such a "no nested triples-terms" restriction in N-Triples 1.2, conversion of the following Turtle 1.2 statement (containing a nested triple-term)
    :s1 :p1 <<( :s2 :p2  ... <<( :sN :pN  :oN )>>  ... )>> .
to N-Triples 1.2 will be the following set of statements:
    :s1 :p1 _:b2 .
    _:b2 rdf:reifies <<( :s2 :p2 _:b3 )>> .
              ...
    _:bN rdf:reiffes <<( :sN :pN :oN )>> .

Thanks,
Souri.
________________________________
From: Pierre-Antoine Champin <pierre-antoine@w3.org>
Sent: Monday, January 27, 2025 7:36 AM
To: Souripriya Das <souripriya.das@oracle.com>; Andy Seaborne <andy@apache.org>; public-rdf-star-wg@w3.org <public-rdf-star-wg@w3.org>
Subject: Re: [External] : Can a triple-term in an N-Triple 1.2 statement have "infinite" number of atomic terms?



On 27/01/2025 13:01, Souripriya Das wrote:
So, in short, N-Triples 1.2 will allow potentially "infinite"-length statements, including ones like the following:

    :s1 :p1 <<( :s2 :p2  ... <<( :sN :pN  :oN )>>  ... )>> .

I would rather say "unbounded" (triple terms, even nested, are always finite), but yes.

Note however that this is an extreme corner case, since most of the time, people would make statements about reifiers rather than about triple terms themselves.


Note that in theory, literals in N-Triples (and in RDF abstract syntax) are also unbounded; same for IRIs. Yet, I assume that all implementations have limits on the size of the IRIs and literals they can accept. So I would not be surprised or concerned if implementations also had limits on the depth of nesting that they accept...

Such a statement in N-Triples 1.2 will contain 2N+1 "atomic" RDF 1.1, possibly unique, terms in a single line (i.e., ending with EOL).

Please confirm.

Thanks,
Souri.



________________________________
From: Pierre-Antoine Champin <pierre-antoine@w3.org><mailto:pierre-antoine@w3.org>
Sent: Monday, January 27, 2025 6:29 AM
To: Souripriya Das <souripriya.das@oracle.com><mailto:souripriya.das@oracle.com>; Andy Seaborne <andy@apache.org><mailto:andy@apache.org>; public-rdf-star-wg@w3.org<mailto:public-rdf-star-wg@w3.org> <public-rdf-star-wg@w3.org><mailto:public-rdf-star-wg@w3.org>
Subject: Re: [External] : Can a triple-term in an N-Triple 1.2 statement have "infinite" number of atomic terms?



On 27/01/2025 11:36, Souripriya Das wrote:
Andy wrote:
>> That's the N-Triples that I'm getting for that Turtle example.
It does not have a nested triple term.

That's good but just to be sure, let me tweak the Turtle 1.2 statement a bit to avoid the use of explicit reifiers.

Would the following statement in Turtle 1.2:
    :s :believes << :s2 :believes << :s3 :p3 :o3 >>  >> .
be a valid statement in N-Triples 1.2 as well?
No, because the '<< ... >>' construct (reification) is only part of Turtle, not of N-Triples.
Not ot be confused with the '<<( ... )>>' construct (triple terms), which is also part of N-Triples.

And yes, recursive triple terms are possible, e.g.


  _:b1 rdf:reifies <<( _:b2 rdf:reifies <<( <tag:s> <tag:p> <tag:o> )>> )>> .


This is valid N-Triples, and contains 1 (asserted) triple.


  best


Or, would it always require use of multiple statements in N-Triples, something like the following?
    :s believes _:b2 .
    _:b2 rdf:reifies <<( :s2 :believes _:b3 )>> .
    _:b3 rdf:reifies <<( :s3 :p3 :o3 )>> .

Thanks,
Souri.

________________________________
From: Andy Seaborne <andy@apache.org><mailto:andy@apache.org>
Sent: Saturday, January 25, 2025 7:09 AM
To: public-rdf-star-wg@w3.org<mailto:public-rdf-star-wg@w3.org> <public-rdf-star-wg@w3.org><mailto:public-rdf-star-wg@w3.org>
Subject: Re: [External] : Can a triple-term in an N-Triple 1.2 statement have "infinite" number of atomic terms?




On 24/01/2025 17:31, Souripriya Das wrote:
In N-Triple 1.1 syntax, a statement consists of exactly three (atomic) terms and I am hoping that N-Triple 1.2 will be a simple extension that will allow 5-term statements as well, subject to the restriction that the predicate for such 5-term statements will always be rdf:reifies.

Thus, the following statement in Turtle 1.2:
    :s :believes << :s2 :believes << :s3 :p3 :o3 ~ :r3 >> ~ :r2 >> .
will be written in N-Triple 1.2 as follows:
    :s believes :r2 .
    :r2 rdf:reifies <<( :s2 :believes :r3 )>> .
    :r3 rdf:reifies <<( :s3 :p3 :o3 )>> .

Is this aligned with the current thinking in the WG?

That's the N-Triples that I'm getting for that Turtle example.
It does not have a nested triple term.


Thanks,
Souri.
________________________________
From: Souripriya Das <souripriya.das@oracle.com><mailto:souripriya.das@oracle.com>
Sent: Thursday, January 23, 2025 11:59 AM
To: RDF-star WG <public-rdf-star-wg@w3.org><mailto:public-rdf-star-wg@w3.org>
Subject: [External] : Can a triple-term in an N-Triple 1.2 statement have "infinite" number of atomic terms?

Would the following be a valid N-Triple 1.2 statement, where n can be, say, 1000?
(There will be a total of 2*1000 + 1 = 2001 "atomic" terms in the triple-term used as the object.)

    :s :p <<( :s1 :p1 <<( :s2 :p2 <<( ... <<(  :sn :pn :on )>> )>> )>> )>> .

The RDF Abstract Syntax allows it and N-triples has concrete syntax for it.
https://www.w3.org/TR/rdf12-concepts/#section-triples<https://urldefense.com/v3/__https://www.w3.org/TR/rdf12-concepts/*section-triples__;Iw!!ACWV5N9M2RV99hQ!JYEvlde5NuL_h5csMvH6AwkIwDQ-0an7pS64QPbyPujF1z1Hq5zPtm0_FQrFPc5jqgNd1kTb5R4zo_5x$>
https://www.w3.org/TR/rdf12-concepts/#section-triple-terms<https://urldefense.com/v3/__https://www.w3.org/TR/rdf12-concepts/*section-triple-terms__;Iw!!ACWV5N9M2RV99hQ!JYEvlde5NuL_h5csMvH6AwkIwDQ-0an7pS64QPbyPujF1z1Hq5zPtm0_FQrFPc5jqgNd1kTb5XDNa7h2$> (2nd point)

Personally, I think nesting in triple terms will not be common, and many levels very, very uncommon.
But the ability to create triple terms for any triple data does lead to providing for nesting.

    Andy



Thanks,
Souri.