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Strong convergence for higher-dimensional hyperbolic manifolds via permutation representations

Determine whether the fundamental group Γ of a closed hyperbolic manifold of dimension d≥3 admits a sequence of random permutation representations that converges strongly to the regular representation λ_Γ, thereby enabling random cover constructions with new eigenvalues asymptotically above the universal bound.

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Background

The survey explains that Hide–Magee’s method for surfaces can be reduced to strong convergence of permutation representations, enabling sharp spectral results for random covers of hyperbolic surfaces.

In higher dimensions, universal upper bounds and parts of the method extend, but the key missing component is whether fundamental groups of such manifolds admit strongly convergent permutation representation sequences.

References

Analogous questions for hyperbolic manifolds in higher dimension remain open. Both the universal upper bound as in Lemma \ref{lem:huber} and the methods of Hide--Magee extend to this setting (see, e.g., ); what is missing is that, at present, it is not known whether the fundamental group of any such manifold admits a strongly convergent sequence of permutation representations.

Strong convergence: a short survey (2510.12520 - Handel, 14 Oct 2025) in Section 4.2.1 (Hyperbolic surfaces)