#1 Non-concept URIs are silently dropped

[Norman Gray]

Consider the following SKOS:

@prefix : <http://www.w3.org/2004/02/skos/core#> .
<> a :ConceptScheme.
<#c1> a :Concept; :prefLabel \"Bah\"@en; :related <#c3>.
<#c3> a :Concept; :prefLabel \"Bad\"@en.
<#c4> a :Concept; :prefLabel \"Wibble\"@en; :related <#xx>.

Note that the <#xx> URI doesn't exist. In a loop

for (SKOSEntity entity :
concept.getSKOSRelatedEntitiesByProperty(dataset,
factory.getSKOSRelatedProperty())) {
// foo
}

the <#c4> :broader <#xx> assertion simply didn't show up, though it
reappeared when I replaced <#xx> with <#c1>. It looks like the triple
is simply removed, because the <#xx> URI doesn't exist.

See attached reduction. This should list #c4 as being related to #xx, but doesn't

[Norman Gray]