prefix : <http://purl.bdrc.io/ontology/core/>
prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#>
prefix bdr: <http://purl.bdrc.io/resource/>
prefix apf: <http://jena.apache.org/ARQ/property#>

# find all resources with duplicate blank nodes
select ?r ?diff
where {
  {
    ?r a :Person .
    graph ?r {
	  select (count(?id) as ?c) (count(distinct ?id) as ?cd)
	  where {
        ?r :personName ?b .
        ?b rdfs:label ?nm .
        ?b a ?type .
        bind (lang(?nm) as ?lang)
        ?id apf:concat (?type "+" ?nm "@" ?lang) .
	  }
     }
  } .
  bind (?c - ?cd as ?diff)
  filter (?diff != 0)
} limit 10


# given a resource, ?R, report the difference of blank nodes and distinct blank nodes
select ?diff
where {
  { select (count(?id) as ?c) (count(distinct ?id) as ?cd)
	where {
      ?R :personName ?b .
      ?b rdfs:label ?nm .
      ?b a ?type .
      bind (lang(?nm) as ?lang)
      ?id apf:concat(?type "+" ?nm "@" ?lang)
	}
  } .
  bind (?c - ?cd as ?diff)
}