On the volume of sectional-hyperbolic sets
Daofei Zhang, Yuntao Zang
TL;DR
This work addresses the volume properties of sectional-hyperbolic sets for flows on a $d$-dimensional manifold ($d\ge 3$). By combining partial hyperbolicity with a graph-transform method, it shows that a transitive sectional-hyperbolic set of positive volume must coincide with the entire manifold, and in fact be uniformly hyperbolic without singularities. The argument uses alpha-limit techniques and invariant-manifold structure to upgrade sectional expansion to full hyperbolicity and to deduce that the set is both stable and unstable saturated, hence equal to $M$. The results extend known zero-volume findings in three dimensions to higher dimensions, linking volume conditions to global hyperbolicity and yielding strong dynamical consequences for sectional-hyperbolic systems.
Abstract
For a transitive sectional-hypebolic set $Λ$ with positive volume on a $d$-dimensional manifold $M$($d\ge3$), we show that $Λ=M$ and $Λ$ is a uniformly hyperbolic set without singularities
