- From: AIFB <tobias.kaefer@kit.edu>
- Date: Wed, 1 Feb 2023 19:22:13 +0100
- To: <public-n3-dev@w3.org>
- CC: <braun@kit.edu>
Dear Henry, for a paper, we also wanted to make sense out of the JSON-LD in VC/LDS from an RDF perspective, and did not find a solution without drawbacks along dimensions such as wide availability of parsers, whether semantics are specified, support for referential opacity, etc. We had a look at named graphs, N3, reified triples, RDF-star, and eventually settled with the latter, see Section 5.1 in [1]. Regards, Tobias [1] https://www.semantic-web-journal.net/content/quantifiable-integrity-linked-data-web (under minor revisions) Am 01.02.23 um 13:18 schrieb Pierre-Antoine Champin: > Henry, all, > > 2 remarks: > > - the problem you identified in Example 1 of VC-Core is indeed > registered as an issue[1] , and should be fixed eventually > > - the conversion from TriG / JSON-LD to N3 performed by Gregg's > distiller is a non-standard interpretation of RDF datasets -- since RDF > datasets have no standard semantics anyway. It assumes that the "name" > of a named graph (IRI or blank node) actually denotes that graph (for > some definition of "that graph") and therefore can be replaced, in N3, > by the corresponding quoted graph. This is consistent with how JSON-LD > is used in VC-core (and it aligns nicely with how this is serialized in > JSON-LD, where the value of "poof", for example, is a JSON object > representing the graph itself, not even requiring an explicit graph > name) -- but this is not the only way one can use named graphs in RDF. > > best > > [1] https://github.com/w3c/vc-data-model/issues/967 > > On 01/02/2023 11:12, Henry Story wrote: >> >>> On 1. Feb 2023, at 08:10, Patrick Hochstenbach >>> <Patrick.Hochstenbach@UGent.be> wrote: >>> >>>> From: Henry Story <henry.story@bblfish.net> >>>> Date: Tuesday, 31 January 2023 at 20:59 >>>> To: public-n3-dev@w3.org <public-n3-dev@w3.org> >>>> Subject: Json-LD to N3? >>>> Hi, >>>> >>>> I find Json-LD a bit opaque to read. Is there a way I can convert it >>>> to n3, >>>> so I can see clearly what the graphs are? >>>> >>>> I can use the json-ld playground to convert it to Nquads, but I could >>>> not see how to get nquads to n3 using eye. >>>> >>>> Henry >>> I always use easyrdf.org for conversions: >>> https://www.easyrdf.org/converter >>> Patrick >> I am trying to convert the examples from the Verifiable Credentials >> Data Model spec such as >> https://www.w3.org/TR/vc-data-model/#example-a-simple-example-of-a-verifiable-credential >> so that I can clearly work out what is a quoted graph and what is not. >> That type >> of information is very much obscured by JSON-LD, even though it is >> essential to >> understanding claims. >> >> Easyrdf does not give me any output when I tried to convert the cleaned >> up Verifiable Claim example [1]. >> >> Greg Kellog pointed me to his RDF distiller >> http://rdf.greggkellogg.net/distiller?command=serialize&format=jsonld&output_format=n3 >> >> And that gives the n3 result as shown in the second snippet of [1]. >> That is consistent >> with the result given by first going through >> https://json-ld.org/playground/ and first >> converting to NQuads (third snipped in [1]) and then using distiller >> to convert nquads to n3. >> >> Interestingly both of those seem to reveal a problem with the first >> example json-ld, as it >> produces the following two triples in n3 >> >> <did:example:c276e12ec21ebfeb1f712ebc6f1> schema:name [], [] . >> >> But one can see quite clearly that the same is true in nquads. >> Greg Kellog suggested this may be a problem with ”value” and ”lang” >> fields not >> having been declared, and indeed when using the jsonld playground it >> helpfully >> suggests using @value and @language instead. With that we then get the >> jsonld in [2] and the nquads and n3 conversions that go with it using >> distiller. >> >> Now I would have expected the graph to be signed to be quoted, and >> linked to by a >> signature. We seem to be having the opposite going on here. >> >> Henry >> >> [1] https://gist.github.com/bblfish/908145116b14486af9dd3460ce14b2c1 >> [2] https://gist.github.com/bblfish/ab1b450c725674a4386cfc391b7e307b >> >> >> >>
Received on Wednesday, 1 February 2023 18:22:30 UTC