А так делаются просто ограничения: "[B]nTopCount[/B]":
$res = CIBlockElement::GetList(
$arOrder = Array("SORT"=>"DESC" ;) ,
$arFilter = array('IBLOCK_ID'=>1),
$arGroupBy = false,
$arNavStartParams = Array([B]"nTopCount"=>4[/B])
;) ;
$res = CIBlockElement::GetList(
$arOrder = Array("SORT"=>"DESC" ;) ,
$arFilter = array('IBLOCK_ID'=>1),
$arGroupBy = false,
$arNavStartParams = Array([B]"nTopCount"=>4[/B])
;) ;