English

Infinitely many Lagrangian fillings

Symplectic Geometry 2022-01-14 v3 Geometric Topology

Abstract

We prove that all maximal-tb Legendrian torus links (n,m) in the standard contact 3-sphere, except for (2,m),(3,3),(3,4) and (3,5), admit infinitely many Lagrangian fillings in the standard symplectic 4-ball. This is proven by constructing infinite order Lagrangian concordances which induce faithful actions of the modular group PSL(2,Z) and the mapping class group M(0,4) into the coordinate rings of algebraic varieties associated to Legendrian links. Our results imply that there exist Lagrangian concordance monoids with subgroups of exponential-growth, and yield Stein surfaces homotopic to a 2-sphere with infinitely many distinct exact Lagrangian surfaces of higher-genus. We also show that there exist infinitely many satellite and hyperbolic knots with Legendrian representatives admitting infinitely many exact Lagrangian fillings.

Keywords

Cite

@article{arxiv.2001.01334,
  title  = {Infinitely many Lagrangian fillings},
  author = {Roger Casals and Honghao Gao},
  journal= {arXiv preprint arXiv:2001.01334},
  year   = {2022}
}

Comments

31 Pages, 15 Figures. A published version of this manuscript will appear in the Annals of Mathematics

R2 v1 2026-06-23T13:03:23.181Z