of points in the plane, a rational number r>0.
in the Euclidean plane, such
that every point in P will covered by a disk with radius r and
center in one of the points in C.
.
[251].
Variation in which the objective is to cover a set of points on the
line by rings of given inner radius r and width w, admits a
PTAS with time complexity exponential in r/w, for arbitrary r
and w the problem is approximable with relative error at most 1/2
[252].
MAXIMUM GEOMETRIC SQUARE PACKING, where the objective is
to place as many squares of a given size within a region in the plane,
also admits a PTAS [251].