AsTMa? Examples (cont'd)

# use of a simple if statement which tests whether the list of collaborated papers is non-empty
function test (map $m) as list
   function sharedAuthorship (string $a) as list return {
      forall exists [ (is-author-of)
                      opus   : $d
                      author : $a ]
             and
             exists [ (is-author-of)
                      opus   : $d
                      author : $b ] in $m return
        ($b, $d)
   }
return {
   forall [ $p (person)
            bn @ sort : $bn ] in $m return {
     if fn:count (sharedAuthorship ($p)) = 0 then
        {$bn}
   }
}

function test (map $m) as list return
   $m / is-author-of / author [ fn:count (. -> is-author-of) < 2 ] / bn