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General non-semisimple relation between the Kuperberg invariant and the Hennings–Kauffman–Radford invariant

Establish the conjectured relationship between the Kuperberg invariant Kup(M, b; H), defined for a finite-dimensional Hopf algebra H and a framing b of a closed oriented 3-manifold M, and the Hennings–Kauffman–Radford invariant HKR(M, φ; D(H)) associated to the Drinfeld double D(H) and a 2-framing φ of M, in the non-semisimple setting. Precisely determine the hypotheses on H and the framing data under which these invariants coincide or otherwise relate for closed oriented 3-manifolds.

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Background

In the semisimple setting, a well-known connection between the Witten–Reshetikhin–Turaev invariants and the Turaev–Viro construction has been established. Analogous structures in the non-semisimple setting include the Kuperberg invariant (for finite-dimensional Hopf algebras) and the Hennings–Kauffman–Radford invariant.

Several partial results support a relation between these invariants, for example equality under specific conditions (e.g., for double balanced Hopf algebras with suitable choices of framing data). The present paper proves a restricted, category-level equality between the chromatic spherical invariant derived from H-mod and HKR for D(H) when H is spherical, but does not resolve the full non-semisimple conjecture for the original Kuperberg invariant across all Hopf algebras.

References

In the non-semisimple setting, it has been analogously conjectured that the Kuperberg invariant Kup, associated to a finite-dimensional Hopf algebra H, is related to the invariant HKR defined using the Drinfeld double of H, D(H). Since the formulation of this conjecture, several partial results have been established supporting this relation.

Chromatic spherical invariant and Hennings invariant of 3-dimensional manifolds (2507.06019 - Reina, 8 Jul 2025) in Introduction