Bott-integrability of overtwisted contact structures
Hansjörg Geiges, Jakob Hedicke, Murat Sağlam
TL;DR
The paper provides a complete criterion for when an overtwisted contact structure on a closed 3-manifold is Bott-integrable, namely that $PD\left(e(\xi)\right)$ must be represented by a graph link. It develops neighbourhood and perturbation results for the Bott integral’s critical set and proves a key Euler-class relation linking critical orbits to $e(\xi)$. It then proves the ‘if’ direction for graph manifolds using Yano’s graph-link criterion, constructs $H_1$-complete Bott-integrable structures on Seifert pieces, and extends them via JSJ- and connected-sum techniques. The paper also provides explicit Bott-integrable examples on the mapping torus of Arnold’s cat map, illustrating the full classification of Bott-integrable structures on a nontrivial graph-manifold family. Collectively, these results connect Reeb dynamics, graph-manifold topology, and Eliashberg’s overtwisted classification to yield a detailed landscape of Bott-integrable overtwisted contact structures on closed 3-manifolds.
Abstract
We show that an overtwisted contact structure on a closed, oriented 3-manifold can be defined by a contact form having a Bott-integrable Reeb flow if and only if the Poincaré dual of its Euler class is represented by a graph link.
