Weak Symplectic Fillings and Holomorphic Curves

TL;DR

This paper investigates weak symplectic fillings of contact 3-manifolds, establishing deformation and obstructions results using holomorphic curves, and introduces new examples and techniques related to fillability and Giroux torsion.

Contribution

It provides new deformation results, obstructions, and examples for weak symplectic fillings, utilizing generalized holomorphic curve techniques and Symplectic Field Theory.

Findings

Weak fillings of planar contact manifolds can be deformed to Stein fillings.

Certain contact manifolds with planar torsion are not weakly fillable.

Weak fillability is preserved under splicing along symplectic pre-Lagrangian tori.

Abstract

We prove several results on weak symplectic fillings of contact 3-manifolds, including: (1) Every weak filling of any planar contact manifold can be deformed to a blow up of a Stein filling. (2) Contact manifolds that have fully separating planar torsion are not weakly fillable - this gives many new examples of contact manifolds without Giroux torsion that have no weak fillings. (3) Weak fillability is preserved under splicing of contact manifolds along symplectic pre-Lagrangian tori - this gives many new examples of contact manifolds without Giroux torsion that are weakly but not strongly fillable. We establish the obstructions to weak fillings via two parallel approaches using holomorphic curves. In the first approach, we generalize the original Gromov-Eliashberg "Bishop disk" argument to study the special case of Giroux torsion via a Bishop family of holomorphic annuli with boundary on an "anchored overtwisted annulus". The second approach uses punctured holomorphic curves, and is based on the observation that every weak filling can be deformed in a collar neighborhood so as to induce a stable Hamiltonian structure on the boundary. This also makes it possible to apply the techniques of Symplectic Field Theory, which we demonstrate in a test case by showing that the distinction between weakly and strongly fillable translates into contact homology as the distinction between twisted and untwisted coefficients.