#
# Items (and their price) belonging to closed auctions with potential annotations
# Annotated nodes: item, auction, (item, auction), itemref
# Card: xmark_0=0, xmark_1=1, xmark_10=0
#
Q1_1 := <$itemref, $price, $y> :-
	triple($x, $p, $y)
	tree(//closed_auction[$x:URI](
   		/itemref/@item[$itemref:VAL],
		/quantity,
		/type{VAL="Featured"},
   		/price[$price:VAL]))
   ;
#
# Items (and their seller) belonging to open auctions with potential annotations
# Annotated nodes: item, auction, (item, auction), seller, itemref, (auction, seller, itemref)
# Card: xmark_0=1, xmark_1=0, xmark_10=2
#
Q2_1 := <$itemref, $seller, $y> :-
	triple($x, <http://www.w3.org/1999/02/22-rdf-syntax-ns#type>, $y)
	triple($x, $p, $y)
	tree(//open_auction[$x:URI](
		/type,
		/interval/start{VAL="04/06/2000"},
		/seller/@person[$seller:VAL],
		/itemref/@item[$itemref:VAL]))
	;
#
# People and items they are interested in.
# Remark: Suggested selection: //person//country{VAL="Germany"} => Card = 2292
# Annotated nodes: item, incategory, person, interest, (item, incategory, person, interest)
# Card: xmark_0=0, xmark_1=1, xmark_10=3
#
Q3_1 := <$item, $name, $y> :-
	triple($x, $p, $y)
	tree(//item[$x:URI](
		/@id[$item:VAL],
		/location,
		//incategory/@category[$cat:VAL]))
	tree(//person(
		/name[$name:VAL],
		//country{VAL="Germany"},
		//interest/@category[$cat:VAL]))
	;

#
# Names of people who have bid on items they were selling
# Annotated nodes: none
# Card: xmark_0=0, xmark_1=0, xmark_10=0
#
Q4_1 := <$y, $email, $z> :-
	triple($x, <http://dbpedia.org/ontology/affiliation>, $y)
	triple($x, $p, $z)
	tree(//open_auction(
		/type,
		/bidder(/personref/@person[$bidder:VAL]),
		/seller/@person[$seller:VAL],
		/itemref[$x:URI]/@item))
	tree(//person(
		/@id[$seller:VAL],
		//country{VAL="United States"},
		//age,
		/emailaddress[$email:VAL],
		/name))
	;

#
# People that have been bidder, seller and buyer. 
# Annotated nodes: person, bidder, seller, buyer, personref, interest, (person, bidder, seller, buyer, personref, interest)
# Card: xmark_0=0, xmark_1=443, xmark_10=?
#
Q5_1 := <$person, $y> :-
	triple($x, $p, $y)
	tree(//person(
		/@id[$person:VAL],
		//country,
		/name[$name:VAL]))
	tree(//bidder[$x:URI](/date{VAL="10/14/2000"} ,/personref/@person[$person:VAL]))
	tree(//seller/@person[$person:VAL])
	;
#
# People watching auctions on item in africa and the exact location of the item.
# Annotated nodes: (item, open_auction, person, watch)
# Card: xmark_0=0, xmark_1=0, xmark_10=0
#
Q6_1 := <$item, $person, $location> :-
	triple($x, <http://dbpedia.org/ontology/Astronaut/timeInSpace>, $y)
	triple($y, $p, $z)
	tree(//person[$x:URI](
		/name[$person:VAL],
		//country[$location:VAL],
		//watch/@open_auction[$auction:VAL]))
	tree(//open_auction(
		/@id[$auction:VAL],
		/type{VAL="Regular"},
		/itemref/@item[$item:VAL]))
	tree(//site//africa/item(
		/@id[$item:VAL],
		/location))
	;
	
#
# Authors (and their homepage) of comments on items sold in closed auctions.
# Remark: Suggested selection: //happiness{VAL="6"} => Card = 1817
# Remark: Extra join possible on //interest/@category => Card = 25, but that yields no result on xmark_0 
# Annotated nodes: (item, incategory, closed_auction, annotation, author, itemref, interest)
# Card: xmark_0=0, xmark_1=0, xmark_10=?
#
Q7_3 := <$auction, $y, $z> :-
	triple($x, $p, $y)
	triple($y, <http://dbpedia.org/ontology/Astronaut/timeInSpace>, $z)
	tree(//interest[$x:URI])
	tree(//watch[$y:URI]/@open_auction[$auction:VAL])
	;
#
# Items whose categories are linked in the property graph
# Annotated nodes: (item, incategory, edge)
# Card: xmark_0=0, xmark_1=?, xmark_10=?
#
Q8_1 := <$item, $x, $y> :-
	triple($x, $p, $o1)
	triple($y, <http://dbpedia.org/ontology/Astronaut/timeInSpace>, $o2)
	tree(//item[$x:URI](
		/@id[$item:VAL],
		/location,
		/quantity{VAL="1"},
		//incategory[$y:URI]/@category[$cat1:VAL]))
	;