H.E. Lomeli and J.D. Meiss
Resonance Zones and Lobe Volumes for Volume-Preserving Maps
(2737K, pdf)

ABSTRACT.  We study exact, volume-preserving diffeomorphisms that have 
heteroclinic connections between a pair of normally hyperbolic invariant 
manifolds. We develop a general theory of lobes, showing that 
the lobe volume is given by an integral of a generating form over the primary intersection, 
a subset of the heteroclinic orbits. Our definition reproduces the classical action formula in the planar, twist map case. For perturbations from a heteroclinic connection, the lobe volume is shown to reduce, to lowest order, to a suitable integral of a Melnikov function.