Cylindrical contact homology for weakly convex contact forms in dimension three

TL;DR

This paper establishes conditions under which cylindrical contact homology is well-defined for weakly convex contact forms on three-manifolds, using a novel cancellation mechanism involving index-2 Reeb orbits.

Contribution

It introduces a new cancellation mechanism for boundary degenerations in cylindrical contact homology for weakly convex contact forms in dimension three.

Findings

Provides criteria for well-defined cylindrical contact homology.

Develops a parity-based cancellation mechanism for boundary degenerations.

Extends understanding of contact homology in weakly convex settings.

Abstract

A contact form $\lambda$ on a closed contact three-manifold $(M,\xi)$ is called weakly convex if either it has no contractible Reeb orbit, or the first Chern class of $\xi$ vanishes on $\pi_2(M)$, and the index of every contractible Reeb orbit is at least $2$. We present conditions for a weakly convex contact form to admit a well-defined cylindrical contact homology. The key point is a cancellation mechanism for boundary degenerations involving index-2 Reeb orbits, based on a parity property of holomorphic planes.