Before revision: Fast constant factor approximation algorithms are devised for a ] problem of intersecting a set of straight line segments with the smallest cardinality set of disks of fixed radii r>0, where the set of segments forms a straight line drawing G=(V,E) of a planar graph without edge crossings.
After revision: Fast constant factor approximation algorithms are devised for a ]-hard problem of intersecting a set of straight line segments with the smallest cardinality set of disks of fixed radii r>0, where the set of segments forms a straight line drawing G=(V,E) of a planar graph without edge crossings.