query: #title: P31 missing on a biography
  # Complex constraint from [[Property talk:P1417]]
  #
  SELECT ?item ?value {
  	?item p:P1417 [ ps:P1417 ?value ].
  	FILTER( REGEX( STR( ?value ), "^(biography\\/[^\\s\\/]+)$" ) ) .
      FILTER NOT EXISTS { ?item wdt:P31 ?e }
  }