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Quantum D-module reduction to GIT quotients (informal conjecture)

Determine and prove that the T-equivariant quantum D-module QDM_T(X), when pulled back to the chart Spec(C[z][[C_{i,N}^\vee]]) corresponding to a chamber C_i in the T-ample cone, becomes (after specified modifications and graded completions) the quantum D-module of the associated smooth GIT quotient Y_i = X//_i T.

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Background

The authors construct a global Kähler moduli space M from the chamber decomposition of the T-ample cone C_T(X) and argue that QDM_T(X) forms a sheaf over a formal subscheme of M×A1_z. The conjecture posits that near each cusp corresponding to a chamber C_i (and GIT quotient Y_i), the sheaf restricts—after suitable modification and completion—to the quantum D-module QDM(Y_i).

This is an abstract D-module counterpart of the Fourier-duality picture, integrating shift (Seidel) operators with Novikov variables and aiming to globalize quantum cohomology across variation of GIT. The subsequent section formulates a more concrete reduction conjecture at the level of solutions (Givental cones).

References

We present the following conjecture, which is currently stated informally. A more rigorous formulation of the conjecture, in terms of solutions of quantum $D$-modules, will be provided in the next section \S\ref{subsec:reduction_conjecture}.

$QDM_T(X)$ pulled back to the chart $Spec(C[z][![C_{i,N}\vee]!])$ is related to the quantum $D$-module of the corresponding GIT quotient $Y_i = X/!/_i T$, after certain modifications and completions.

Fourier analysis of equivariant quantum cohomology (2501.18849 - Iritani, 31 Jan 2025) in Conjecture (label conj:reduction_QDM), Section 2.4 (Equivariant ample cone and the Kähler moduli space)