Fuse subset descriptions

fuse_less_described.sparql

PREFIX : <http://example.com/>

DELETE {
  ?r1 ?outP ?outO .
  ?inS ?inP ?r1 .
}
INSERT {
  ?inS ?inP ?r2 .
}
WHERE {
  {
    SELECT DISTINCT ?r1 ?r2
    WHERE {
      # Select resources to fuse. 
      ?r1 a :C .
      ?r2 a :C .
      FILTER (!sameTerm(?r1, ?r2)) 

      # There's no property-value pair of ?r1 that ?r2 doesn't have.
      FILTER NOT EXISTS {
        ?r1 ?p ?o .
        FILTER NOT EXISTS {
          ?r2 ?p ?o .
        }
      }
    }
  }
  ?r1 ?outP ?outO .
  OPTIONAL {
    ?inS ?inP ?r1 .
  }
}