Flop Invariance of Refined Topological Vertex and Link Homologies
Masato Taki
TL;DR
The paper extends the refined, two-parameter topological string formalism to local toric Calabi–Yau geometries, analyzing flop behavior of refined amplitudes using the refined topological vertex and free-fermion techniques. It proves refined flop invariance for subdiagrams and links the invariant amplitudes to homological Hopf-link invariants via slicing invariance, proposing a closed-form superpolynomial for the Hopf link and validating it in simple cases. A key technical advance is a transpose identity for skew Schur functions that underpins the flop transformation, enabling more efficient computation of Hopf-link homologies. Collectively, the results provide refined, computable expressions for Hopf-link invariants and deepen the connection between refined topological strings and link homologies.
Abstract
It has been proposed recently that the topological A-model string theory on local toric Calabi-Yau manifolds has a two parameter extension. Amplitudes of the two parameter topological strings can be computed using a diagrammatic method called the refined topological vertex. In this paper we study properties of the refined amplitudes under the flop transition of toric Calabi-Yau three-folds. We also discuss that the slicing invariance and the flop transition imply a simple formula for the homological sl(N) invariants of the Hopf link. The new expression for the invariants gives a simple refinement of the Hopf link invariant of Chern-Simons theory.
