title: When Lyapunov exponents fail to exist.
abstract: We describe a simple continuous-time flow such that Lyapunov exponents fail to exist at nearly every point in the phase space R2 , despite the fact that the flow admits a unique natural measure. This example illustrates that the existence of Lyapunov exponents is a subtle question for systems that are not conservative.
authors.affiliation: Courant Institute of Mathematical Sciences, New York University, New York, New York 10012, USA.
authors.forename: William
authors.initials: W
authors.lastname: Ott
authors.forename: James A
authors.initials: JA
authors.lastname: Yorke