  One strategy for devising a definition for chaos is to begin with discrete maps and then generalize to the continuous case. For example, if one begins with a continuous system, by using a Poincaré surface of section—roughly, a two-dimensional plane is defined and one plots the intersections of trajectories with this plane—a discrete map can be generated. If the original continuous system exhibits chaotic behavior, then the discrete map generated by the surface of section will also be chaotic because the surface of section will have the same topological properties as the continuous system. Robert Devaney’s influential definition of chaos (1989) was proposed in this fashion. 