English

Simplified SFT moduli spaces for Legendrian links

Symplectic Geometry 2025-07-16 v4 Geometric Topology

Abstract

We study moduli spaces M\mathcal{M} of holomorphic maps UU from Riemann surfaces to R4\mathbb{R}^{4} with boundaries on the Lagrangian cylinder over a Legendrian link Λ(R3,ξstd)\Lambda \subset (\mathbb{R}^{3}, \xi_{std}). We allow our domains, Σ\Sigma, to have non-trivial topology in which case M\mathcal{M} is the zero locus of an obstruction function O\mathcal{O}, sending a moduli space of holomorphic maps in C\mathbb{C} to H1(Σ)H^{1}(\Sigma). In general, O1(0)\mathcal{O}^{-1}(0) is not combinatorially computable. However after a Legendrian isotopy, Λ\Lambda can be made left-right-simple, implying that any UU of index 11 is a disk with one or two positive punctures for which πCU\pi_{\mathbb{C}}\circ U is an embedding. Moreover, any UU of index 22 is either a disk or an annulus with πCU\pi_{\mathbb{C}} \circ U simply covered and without interior critical points. Therefore any SFT invariant of Λ\Lambda is combinatorially computable using only disks with 2\leq 2 positive punctures.

Keywords

Cite

@article{arxiv.2104.00505,
  title  = {Simplified SFT moduli spaces for Legendrian links},
  author = {Russell Avdek},
  journal= {arXiv preprint arXiv:2104.00505},
  year   = {2025}
}

Comments

42 pages. V4: Updates based on referee feedback

R2 v1 2026-06-24T00:46:33.048Z