with the assumption that we can determine in one step the distance
between two points on the plane or the center of a disk with the necessary precision.
(Note that it is possible to speed up that process by sorting the disk centers in O(l*)
prespecified subsquares of the region and then determining in which of the
subsquares there could be the potential covering disk by binary search in time
O(log I).) The two nested applications of the shifting strategy add another factor 1’
to our global time bound.
For d > 2 one proceeds analogously with d nested applications of the shifting
strategy. Q.E.D.