Top Concepts Having Broader Concepts

[riannella]

I've tested my Skos ontology using qSKOS (the frontend at https://skos-play.sparna.fr/) and it raised fail error for "Top Concepts Having Broader Concepts"

I have matched some Top Concepts to external skos vocabularies (where they are just skos concepts but broader in nature).

According to: https://www.w3.org/TR/skos-reference/#L2446
The property skos:hasTopConcept is, by convention, used to link a concept scheme to the SKOS concept(s) which are topmost in the hierarchical relations for that scheme
This seems to say that a Scheme has a Top Concept only local to itself?

[danmichaelo]

Are you using skos:broader or skos:broadMatch in this case? If there's inference involved, it might not make a difference since skos:broadMatch is a subproperty of skos:broader, and I haven't tested, but intuitively I would have assumed skos:broadMatch to be OK for top concepts, but not skos:broader, since skos:broader is normally used for relations within the vocabulary and skos:broadMatch for relations between vocabularies, even though the SKOS model itself does not restrict this formally.

[riannella]

I am using skos:broadMatch.
Here is a simple example that fails with "Top Concepts Having Broader Concepts"

====
@Prefix skos: http://www.w3.org/2004/02/skos/core# .
@Prefix a: http://example.com/ .

a:CS1 a skos:ConceptScheme;
skos:prefLabel "My Scheme"@en;
skos:hasTopConcept a:C1 ;
.
a:C1 a skos:Concept ;
skos:prefLabel "My Movie"@en ;
skos:inScheme a:CS1 ;
skos:broadMatch https://schema.org/Movie ;
.