Rigidity and Realizability for Tropical Curves in Dimension 3
Jeff Hicks
TL;DR
The paper addresses unobstructedness for Lagrangian lifts of tropical curves in dimension 3 and its implications for realizability on the mirror side. It develops an unobstructedness criterion on the A-side from cyclic $A_\infty$ structures via a limiting loop grading $\mathrm{Grd}_\infty$, and then shows that rigid tropical curves with pair-of-pants decompositions yield unobstructed Lagrangian lifts $L_V$ in a tropical abelian threefold. Under a homological mirror symmetry framework, these unobstructed lifts imply a $B$-realization $Y_V$ in the mirror $X^B$, connecting tropical rigidity to algebraic realizability. The work also provides concrete examples illustrating rigidity, stabilization, and the calculation of relevant cohomology/functions that govern unobstructedness, thereby extending realizability criteria beyond previously known cases.
Abstract
We present an unobstructedness criterion for Lagrangian threefolds $L\subset X^A$ using the $H_1(L)$-class associated with the boundary of a pseudoholomorphic disk. As an application, let $X^A\to Q$ be a Lagrangian torus fibration whose base $Q$ is a tropical abelian threefold. Given $V\subset Q$ a rigid tropical curve with a pair-of-pants decomposition, we prove that the Lagrangian lift $L_V\subset X^A$ is unobstructed. Provided that an appropriate homological mirror symmetry statement holds, this implies the existence of a realization $Y_V$ in the mirror abelian threefold $X^B\to Q$.
