CGAL 4.12.1 - 2D and 3D Linear Geometry Kernel
CGAL::lexicographically_xy_smaller()
CGAL::compare_xy()
CGAL::lexicographically_xy_larger()
CGAL::lexicographically_xy_larger_or_equal()
CGAL::lexicographically_xy_smaller_or_equal()
returns true iff p is lexicographically smaller than q with respect to $$xy$$ order.