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”