/a></h2>

<p>Exact arithmetic may be used instead of floating point.
Singularities such as coplanar points can either be handled
directly or the input can be symbolically perturbed. Using exact
arithmetic is slower than using floating point arithmetic and the
output may take more space. Chaining a sequence of operations
increases the time and space required. Some operations are
difficult to do.</p>

<p><a href=http://www.cgal.org/>CGAL</a> includes a practical implementation
of symbolic perturbation.  It us