# Which events are attended by Tamara and Robert

PREFIX  dc:   <http://purl.org/dc/elements/1.1/>
PREFIX  cal:  <http://www.example.org/Calendar#>
PREFIX  rdf:  <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX : <.>

SELECT ?title1 ?start1 ?sTime1 ?end1 ?eTime1
FROM NAMED <SRobert.rdf>
FROM NAMED <STamara.rdf>

WHERE {

        GRAPH :SRobert.rdf {
          ?x dc:title ?title1.
          ?x cal:date ?date1.	
          ?y cal:startDay ?start1.
	  ?y cal:startTime ?sTime1.
	  ?y cal:endTime ?eTime1.
	  ?y cal:endDay ?end1.
	
	  FILTER (?date1 =?y).
        }.
        GRAPH :STamara.rdf {
          ?z dc:title ?title2.
          ?z cal:date ?date2.	
          ?w cal:startDay ?start2.
	  ?w cal:startTime ?sTime2.
	  ?w cal:endTime ?eTime2.
	  ?w cal:endDay ?end2.
	  FILTER(?date2 = ?w).
	}.
	  
        FILTER(?title1 = ?title2).
        FILTER(?start1 = ?start2).
        FILTER(?end1 =?end2).
        FILTER(?sTime1 = ?sTime2).
        FILTER(?eTime1 = ?eTime2). 
        
      }