PREFIX skos: <http://www.w3.org/2004/02/skos/core#>
PREFIX : <http://purl.org/net/schemarama#>
CONSTRUCT
{
  [] a :Warning;
    :message 'Concept [1] is declared as top concept in scheme [2], and has broader [3] in same scheme.';
    :implicated ( ?x ?s ?y);
  .
}
WHERE
{
  ?x skos:broader ?y.
  ?s skos:hasTopConcept ?x.
  ?y skos:inScheme ?s.
}