Operations

x = pointer to an object containing some key

Make-Set(x)
$\;\;\;\;\;$Create new set S_x with one member x
$\;\;\;\;\;$Representative of S_x is x
$\;\;\;\;\;$Disjoint set = Disjoint set + S_x

Union(x,y)
$\;\;\;\;\;$S_x = set containing x
$\;\;\;\;\;$S_y = set containing y
$\;\;\;\;\;$ $S_u = S_x \cup S_y$
$\;\;\;\;\;$rep(S_u) = rep(S_x) or rep(S_y) $\;\;\;\;\;$ $\;\;\;\;\;$; or any other object in S_u
$\;\;\;\;\;$Disjoint set = Disjoint set - S_x - S_y + S_u

Find-Set(x)
$\;\;\;\;\;$S_x = set containing x
$\;\;\;\;\;$return rep(S_x)