Convergence of the ballistic-deposition growth speed constant

Prove the convergence of the rescaled ballistic-deposition growth speed $Kv_K$ as the strip size $K$ tends to infinity, where $v_K$ is the almost-sure limiting height-growth speed on a cyclic strip of $K$ sites.

Background

For ballistic deposition on a cyclic strip with KK sites, the paper proves that all sites share a common almost-sure growth speed vKv_K and establishes the bounds 3/KcvKc3e/K3/Kc v_Kc 3e/K. Numerical evidence suggests that KvKKv_K increases with KK toward a limit near $4.06$, while the earlier conjectural value $4/K$ is shown not to be exact. The equality of sitewise growth speeds is proved, but convergence of the rescaled constants KvKKv_K remains unresolved.

References

We do not prove the convergence of $Kv_K$.

— Gaps between roots in ballistic deposition on a strip: linear variance, Gaussian limits and a Poisson regime  (2610.21094 - Matijasevick, 15 Oct 2026) in Subsection “The growth speed,” Section 6 (Further results)