Dynamic near-linear ε-additive Steiner spanners in hyperbolic space and removal of α(n) factor

Develop dynamic ε-additive Steiner spanners for n points in d-dimensional hyperbolic space H^d with near-linear edge count and efficient update time, and eliminate the α(n) factor appearing in current edge bounds (e.g., O_{ε,d}(n·log α(n))).

Background

The paper gives an ε-additive Steiner spanner in Hd with edge count close to linear, but the construction is static and carries a dependence on the inverse Ackermann function via transitive closure spanners. The authors highlight the desirability of dynamic maintenance for such additive spanners.

They explicitly pose achieving near-linear size in the dynamic setting and removing the α(n) dependence as open problems, pointing to potential algorithmic and geometric advances required to meet both goals.

References

We believe that the following are especially promising open problems for future work: Is there a near-linear size $\varepsilon$-additive Steiner spanner in hyperbolic space that is dynamic? Can we remove the $\alpha(n)$ factor in its edge count?

Near-Optimal Dynamic Steiner Spanners for Constant-Curvature Spaces  (2509.01443 - Kisfaludi-Bak et al., 1 Sep 2025) in Section Conclusion