$($define $($unique$-$pairs lst$)$

$($if $($null$?$ lst$)$

$\text{'}()$ ; If the list is empty, return an empty list of pairs

$($append

$($map $($lambda $($x$)($cons $($car lst$)$ x$))($cdr lst$))$ ; Pair the first element with each of the remaining elements

$($unique$-$pairs $($cdr lst$)))))$ ; Recur with the rest of the list