The Relative Gromov Width of Lagrangian Cobordisms between Legendrians

TL;DR

This paper establishes bounds on the relative Gromov width of Lagrangian cobordisms between Legendrian submanifolds, linking geometric sizes to algebraic invariants and Reeb chord neighborhoods.

Contribution

It introduces a novel method to bound the Gromov width using Legendrian Contact Homology and explicit Reeb chord constructions, connecting algebraic and geometric aspects.

Findings

Upper bounds from $J$-holomorphic disks passing through embedded balls.

Lower bounds from neighborhoods of Reeb chords.

Relationship between Gromov width and cobordism length.

Abstract

We obtain upper and lower bounds for the relative Gromov width of Lagrangian cobordisms between Legendrian submanifolds. Upper bounds arise from the existence of $J$-holomorphic disks with boundary on the Lagrangian cobordism that pass through the center of any given symplectically embedded ball. The areas of these disks --- and hence the sizes of these balls --- are controlled by a real-valued fundamental capacity, a quantity derived from the algebraic structure of filtered linearized Legendrian Contact Homology of the Legendrian at the top of the cobordism. Lower bounds come from explicit constructions that use neighborhoods of Reeb chords in the Legendrian ends. We also study relationships between the relative Gromov width and another quantitative measurement, the length of a Lagrangian cobordism.