Gary, Based on the W3C wiki description <https://www.w3.org/wiki/BlankNodes>, that is consistent.
1) Blank nodes must not have an IRI, like Coordinate and CreationInformation instances 2) Blank nodes may apply to more than one IRI (RDF graph node), like Coordinate and CreationInformation instances I assume you can assign blank nodes to both an entire datatype and to fields within that datatype at any nesting level. Regards, David On Mon, Mar 20, 2023 at 3:25 PM Gary O'Neall <[email protected]> wrote: > Thanks David for the additional info. > > > > I was planning allowing the fields of “data types” as objects in RDF > triples in SPDX 3.0. The difference between Elements and “data types” was > whether URI types were required or if the object could be an > anonymous/blank node. > > > > Is this consistent with the discussion in the Serialization meeting? > > > > Gary > > > > *From:* [email protected] <[email protected]> *On Behalf Of > *David Kemp > *Sent:* Sunday, March 19, 2023 12:07 PM > *To:* SPDX-list <[email protected]> > *Subject:* [spdx-tech] Serialization: Ontologies vs Datatypes > > > > At the SPDX Serialisation Meeting 2023-03-16: > > Sean presented a deck of slides that he and Alexios had created to explain > concepts relating to JSON-LD and RDF with regard to SPDX. The presentation > covered JSON, JSON-LD, context maps and ontologies. > > > The discussion included Alexios' toy example of Coordinate, and whether it > is a linked (referenceable) item in an ontology or not. > 1) SPDX Element instances are referenceable by SpdxId, an IRI > > 2) Instances of Datatypes are plain values, they do not have reference IDs > > A third option was discussed, whether Coordinate could be an ontological > element (a subject or object, connected by a predicate in an ontology > graph), in which case each instance of a Coordinate would need an IRI that > is not an SpdxId in addition to its value (latitude and longitude). > > The case of Central Park was discussed, which would be modeled as a > "Place" with a name, image, and an ordered list of Coordinates (not a set) > that establishes its perimeter. The southeast corner of the park, 5th > Avenue and W. 58th St, has coordinate 40.76376383066618, -73.973564545299. > This instance is not an ontological item because it is also on the > perimeter of 5th Avenue that exists independently of Central Park. The > identical coordinate would have at least three different IRIs (as > coordinates of one park, two streets, plus innumerable people standing on > that corner) if it were considered a referenceable RDF item. Therefore it > is not, it is just a value. > > The SPDX model accurately expresses the semantics of Datatypes: > CreationInformation, ExternalIdentifier, PositiveIntegerRange, etc, are > data types: > > These types have value-type / struct semantics - equality is determined by > comparing values and they MUST NOT be referenced by name across documents. > > > We should add a list (like the boundary of Central Park) that cannot be a > set to Alexios' toy serialization example, even if SPDX does not have any > use cases for an ordered list, to ensure that the modeling methodology is > complete. > > > -=-=-=-=-=-=-=-=-=-=-=- Links: You receive all messages sent to this group. View/Reply Online (#5047): https://lists.spdx.org/g/Spdx-tech/message/5047 Mute This Topic: https://lists.spdx.org/mt/97716744/21656 Group Owner: [email protected] Unsubscribe: https://lists.spdx.org/g/Spdx-tech/unsub [[email protected]] -=-=-=-=-=-=-=-=-=-=-=-
