for $item in collection("sortieudpipe-slurp_3476.xml")//item
let $frere:=$item/following-sibling::item[1]
let $frere2:=$frere/following-sibling::item[1]
let $frere3:=$frere2/following-sibling::item[1]
where (($item/a[4]="NOUN") and (contains($frere/a[4], "ADP")) and ($frere2/a[4]="NOUN") and ($frere3/a[4]="ADP"))
let $terme:=string-join (($item/a[2]," ",$frere/a[2]," ",$frere2/a[2]," ",$frere3/a[2]," "))
group by $regroupement:=$terme
order by count ($terme) descending
return string-join(($regroupement,count($terme))," ")