A refinement of the Hofer-Zehnder theorem on the existence of closed trajectories near a hypersurface
arXiv:math/0305148
Abstract
The Hofer-Zehnder theorem states that almost every hypersurface in a thickening of a hypersurface in a symplectic manifold carries a closed characteristic provided that bounds a compact submanifold and has finite capacity. We show that it is enough to assume that the thickening of has finite capacity.
4 pages, 1 figure