FUNCTION UNION,A,B
;+
;C=UNION(A,B) is the union of the sets A and B. It is assumed
;that A and B have some form of integer values. That is, they
;come from the set of non-negative integers.
;-

mx=MAX([A,B])
T=INTARR(mx+1)
T[A]=1
T[B]=1
S=WHERE(T EQ 1)
RETURN,S
END