Motivated by the problem of labeling maps, we investigate the problem of computing a large non-intersecting subset in a set of n rectangles in the plane. Our results are as follows. In Onlogn time, we can nd an Ologn-factor approximation of the maximum subset in a set of n arbitrary axis-parallel rectangles in the plane. If all rectangles have unit height, we can nd a 2-approximation in Onlogn time. Extending this result, we obtain a 1 + 1 k -approximation in time Onlogn + n2k,1 time, for
Pankaj K. Agarwal, Marc J. van Kreveld, Subhash Su