similar appellation yielding other direction specific indices, the Lyapounov characteristic exponents, 42 (Oseledec, 1968; Eckmann and Ruelle, 1985; Ruelle, 1990; Ott et al, 1994). In this context, the instability is not one of perturbative escape from a fixed point, but of the average rate with which th

rt initial values could be found close together in the limit set. This behavior was called “sensitivity to initial conditions” by David Ruelle (1978; Ruelle and Takens, 19771). It is noteworthy, however, that over a range of values of the parameters, the overall pattern of the orbits of the Lorenz attract