G. Lapeyre et al., Comment on "Finding finite-time invariant manifolds in two-dimensional velocity fields" [Chaos 10, 99, (2000)], CHAOS, 11(2), 2001, pp. 427-430
This note serves as a commentary of the paper of Haller [Chaos 10, 99 (2000
)] on techniques for detecting invariant manifolds. Here we show that the c
riterion of Haller can be improved in two ways. First, by using the strain
basis reference frame, a more efficient version of theorem 1 of Haller (200
0) allows to better detect the manifolds. Second, we emphasize the need to
nondimensionalize the estimate of hyperbolic persistence. These statements
are illustrated by the example of the Kida ellipse. (C) 2001 American Insti
tute of Physics.