CGAL::is_theta_monotone

#include <CGAL/global_functions_spherical_kernel_3.h>

bool	is_theta_monotone ( Circular_arc_3<SphericalKernel> a, Sphere_3<SphericalKernel> sphere)
		Tests whether the arc a is -monotone, i.e. the intersection of any meridian anchored at the poles sphere and the arc a is reduced to at most one point in general, and two points if a pole of sphere is an endpoint of the arc. Note that a bipolar circle has no such arcs. Precondition:  a lies on sphere, and the supporting circle of a is not bipolar.