Arithmeticity of hyperbolic link complements

Determine which hyperbolic link complements have arithmetic fundamental groups, extending the known classification of arithmetic hyperbolic knot complements and the arithmeticity result for the (2n)-chain links.

Background

The paper notes that Reid proved the figure-eight knot complement is the only hyperbolic knot complement with arithmetic fundamental group. It then contrasts this with link complements, many of which are related to quotients of hyperbolic 3-space by ideal, right-angled reflection groups.

For the (2n)-chain links, the cited theorem gives arithmeticity exactly for n=3 or 4. A broader classification for hyperbolic link complements remains unresolved, particularly beyond cases whose fundamental groups are themselves hyperbolic reflection groups.

References

The analogous problem is still open for link complements.

— Arithmetic Polyhedra  (2609.05349 - Allcock et al., 4 Sep 2026) in Section 1, subsection “Application to Hyperbolic Link Complements”