Specification of the Traits Classes for CGAL Arrangements of Curves

This document describes the specification of the new and improved traits classes for CGAL arrangements of curves. It is the product of collaboration between TAU in Israel, INRIA in France, and MPI in Germany. Together we were able to tighten the set of requirements of the arrangement traits, that is the interface between arrangements and the primitives they use. The dialog also emphasized the need for a redesign and a new implementation of the sweep-line module. This has been successfully completed recently.