Comment:
There is a PTAS also for other convex objects, e.g. squares, and in
d
-dimensional Euclidean space for
[
169
].
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
[
170
].
The
Maximum Geometric Square Packing Problem
, where the objective is
to place as many squares of a given size within a region in the plane,
also admits a PTAS [
169
].