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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.

Flop Invariance of Refined Topological Vertex and Link Homologies

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.

Paper Structure

This paper contains 9 sections, 76 equations, 3 figures.

Figures (3)

  • Figure 1: The refined topological vertex $\mathop C\nolimits_{\lambda \mu \nu } (t,q)$
  • Figure 2: The two resolved conifolds (a) and (b) are related via the flop transition.
  • Figure 3: The superpolynomial $\bar{\mathcal{P}}$ and $\hat{Z}$ are related under the slicing invariance and the flop transition.