Web-Technologies

Consider the following XML DTD describing course information in a university:

<!ELEMENT Univ (Course+, Prof+)>
<!ELEMENT Course (Title, Eval*)>
<!ATTLIST Course Number ID #REQUIRED Instructor IDREF #IMPLIED>
<!ELEMENT Title (#PCDATA)>
<!ELEMENT Eval (#PCDATA)>
<!ATTLIST Eval Score CDATA #REQUIRED>
<!ELEMENT Prof EMPTY>
<!ATTLIST Prof Name ID #REQUIRED Teaches IDREF #IMPLIED>

What is returned by the following XQuery?

let $as := //@Score
for $c in /Univ/Course[Eval]
let $cs := $c/Eval?@Score
where min($cs) > avg($as)
return $c