Re: JSON-LD-star patterns

A follow on to this, with some hypothetical multi-statement reifiers acting like graphs. Consider JSON-LD Example 115 [1] about making statements about a graph.

{
  "@context": {
    "generatedAt": {
      "@id": "http://www.w3.org/ns/prov#generatedAtTime",
      "@type": "http://www.w3.org/2001/XMLSchema#dateTime"
    },
    "Person": "http://xmlns.com/foaf/0.1/Person",
    "name": "http://xmlns.com/foaf/0.1/name",
    "knows": {"@id": "http://xmlns.com/foaf/0.1/knows", "@type": "@id"}
  },
  "@id": "http://example.org/foaf-graph",
  "generatedAt": "2012-04-09T00:00:00",
  "@graph": [
    {
      "@id": "http://manu.sporny.org/about#manu",
      "@type": "Person",
      "name": "Manu Sporny",
      "knows": "https://greggkellogg.net/foaf#me"
    }, {
      "@id": "https://greggkellogg.net/foaf#me",
      "@type": "Person",
      "name": "Gregg Kellogg",
      "knows": "http://manu.sporny.org/about#manu"
    }
  ]
}
This results in the following TriG:
@prefix foaf: <http://xmlns.com/foaf/0.1/> .
@prefix prov: <http://www.w3.org/ns/prov#> .
@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .

<http://example.org/foaf-graph> prov:generatedAtTime "2012-04-09T00:00:00"^^xsd:dateTime .

<http://example.org/foaf-graph> {
  <http://manu.sporny.org/about#manu> a foaf:Person;
     foaf:name "Manu Sporny";
     foaf:knows <https://greggkellogg.net/foaf#me> .

  <https://greggkellogg.net/foaf#me> a foaf:Person;
     foaf:name "Gregg Kellogg";
     foaf:knows <http://manu.sporny.org/about#manu> .
}
If you were to use @reifier instead of @graph, you’d get something like the following Turtle:
@prefix foaf: <http://xmlns.com/foaf/0.1/> .
@prefix prov: <http://www.w3.org/ns/prov#> .
@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .

<http://example.org/foaf-graph> prov:generatedAtTime "2012-04-09T00:00:00"^^xsd:dateTime;
  rdf:reifies <<( <http://manu.sporny.org/about#manu> a foaf:Person )>>,
              <<( <http://manu.sporny.org/about#manu> foaf:name “Manu Sporny” )>>,
              <<( <http://manu.sporny.org/about#manu> foaf:knows <https://greggkellogg.net/foaf#me> )>>,
              <<( <https://greggkellogg.net/foaf#me>  a foaf:Person )>>,
              <<( <https://greggkellogg.net/foaf#me>  foaf:name “Gregg Kellogg” )>>,
              <<( <https://greggkellogg.net/foaf#me>  foaf:knows <http://manu.sporny.org/about#manu> )>> .
Gregg Kellogg
gregg@greggkellogg.net

[1] https://www.w3.org/TR/json-ld11/

> On Sep 14, 2024, at 1:13 PM, Gregg Kellogg <gregg@greggkellogg.net> wrote:
> 
> The JSON-LD CG (specifically, Pierre-Antoine, Niklas and myself) started a draft on JSON-LD-star [1] in 2020. Since then, the target has changed, so we’ve created an issue to consider how this might adapt to Triple Terms, Reifying Triples, and Annotations [2].
> 
> Basically, the idea is to add three new keywords to JSON-LD, @reifies, @triple, and @annotation. JSON-LD encodes RDF iin JSON using Node Objects, which can represent a subject/identifier, @type and properties based on key/value entries in a map. This proposal uses @reifies, @triple, and @annotation as special properties to encode triple terms.
> 
> At the most fundamental level, @triple is intended to encode a single triple with an @id and a single-valued property.
> 
> {
>  "@context": {
>    "@base": "http://example.org/",
>    "@vocab": "http://example.org/",
>    "rdf": "http://www.w3.org/1999/02/22-rdf-syntax-ns#",
>  },
>  "rdf:reifies": {
>    "@triple": {
>      "@id": "bob",
>      "age": 42
>    }
>  },
>  "certainty": 0.8
> }
> 
> This would be equivalent to the following Turtle:
> 
> BASE <http://example.org/>
> PREFIX : <http://example.org/>
> PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#”>
> 
> [ rdf:reifies <<( :bob :age 42 ))> ]; :certainty: 0.8 .
> 
> In this case, since there is no explicit @id at the top level, a blank node is generated, which is used as the reifier.
> 
> The @reifies keyword can be used to compact this, and holds the potentially for reifying more than one triple:
> 
> {
>  "@context": {
>    "@base": "http://example.org/",
>    "@vocab": "http://example.org/",
>    "rdf": "http://www.w3.org/1999/02/22-rdf-syntax-ns#",
>  },
>  “@id”: “reifier”,
>  "@reifies": {
>    "@id": "bob",
>    "age": 42
>  },
>  "certainty": 0.8
> }
> 
> The example shows a single triple, but in principle, @reifies could take an array of objects, each with a different @id, and each object may have one or more properties; each of these could turn into a separate triple term referenced by the same reifier. This perticular example uses an expicit reifier, so the resulting Turtle would be:
> 
> BASE <http://example.org/>
> PREFIX : <http://example.org/>
> PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#”>
> 
> :reifier rdf:reifies <<( :bob :age 42 ))>; :certainty: 0.8 .
> 
> It’s an open question if downstream relationships would also be reified; they’re not in Turtle.
> 
> The annotation syntax is similar to Turtle:
> 
> {
>  "@context": {
>    "@base": "http://example.org/",
>    "@vocab": "http://example.org/"
>  },
>  "@id": "bob",
>  "age": {
>    "@value": 42,
>    "@annotation": {
>      "@id": "_:anno",
>      "certainty": 0.8
>    }
>  }
> }
> 
> In this case, the annotation may have it’s own reifier assigned (here ’s _:anno), or one can be assigned automatically. This would be equivalent to the following Turtle:
> 
> :bob :age 42 ~ _:anno {| :certainty  8.0E-1 |} .
> 
> Note that in the Reification example, the @refiies keyword acts much like @graph. If it were restated as follows, it would use the named graph syntax, which is common in Verifiable Claims.
> 
> {
>  "@context": {
>    "@base": "http://example.org/",
>    "@vocab": "http://example.org/",
>    "rdf": "http://www.w3.org/1999/02/22-rdf-syntax-ns#"
>  },
>  "@id": "reifier",
>  "@graph": {
>    "@id": "bob",
>    "age": 42
>  },
>  "certainty": 0.8
> }
> 
> This results in the following TriG.
> 
> BASE <http://example.org/>
> PREFIX : <http://example.org/>
> PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#”>
> PREFIX xsd: <http://www.w3.org/2001/XMLSchema#> .
> 
> :reifier :certainty 8.0E-1 .
> 
> :reifier {
>  :bob :age 42 .
> }
> 
> This suggests that there may be a way to describe named graphs using reification.
> 
> Gregg Kellogg
> gregg@greggkellogg.net
> 
> [1] https://json-ld.github.io/json-ld-star/
> [2] https://github.com/json-ld/json-ld-star/issues/49