-- card: 8607 from stack: in -- bmap block id: 0 -- flags: 0000 -- background id: 2619 -- name: -- part contents for background part 23 ----- text ----- • Each positive Lyapunov exponent represents a "direction" in which the system experiences the stretching that causes unpredictability. • The exponential expansion indicated by a positive Lyapunov exponent is incompatible with motion on a bounded attractor unless some sort of folding takes place. • An attractor with one or more positive Lyapunov exponents is "chaotic" or "strange".