Proof of the Lyons--White Conjecture
Abstract
Let Dn be the dihedral group of order 2n. Consider a continuous-time random walk on Dn driven by arbitrary symmetric rates whose support generates Dn. For p∈[1,∞], we say the pair (Dn,p) is rate-monotonic if for each fixed time t, the ℓp-distance between the random walk's distribution at time t and the uniform distribution is monotonically decreasing as a function of the rates. Lyons and White proved that (Dn,2) and (Dn,∞) are rate-monotonic. Somewhat counterintuitively, they found several pairs (Dn,p) with p∈[1,1.997]∪[2.001,3.999]∪[4.001,5.995] that are not rate-monotonic, and they asked whether any such pairs exist with p=4 or p=6. We resolve their question, proving that (Dn,2m) is rate-monotonic for all positive integers m and n. In fact, we prove a generalization of this result to a broader family of groups that includes generalized dihedral groups, dicyclic groups, and generalized quaternion groups. In the other direction, we prove that for every real p≥ 1 that is not an even integer, there exists a positive integer n such that (Dn,p) is not rate-monotonic. The results of this paper were formally verified in Lean by AxiomProver assuming standard literature.
Related
BibTeX
@misc{defant2026proof,
title = {{Proof of the Lyons--White Conjecture}},
author = {Colin Defant and Ken Ono},
howpublished = {arXiv},
year = {2026},
month = aug,
doi = {10.48550/arxiv.2608.27708},
eprint = {2608.27708},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2608.27708},
note = {CC0},
}
RIS
TY - UNPB
TI - Proof of the Lyons--White Conjecture
AU - Colin Defant
AU - Ken Ono
PY - 2026
DA - 2026/08/27
PB - arXiv
DO - 10.48550/arxiv.2608.27708
UR - https://arxiv.org/abs/2608.27708
AB - Let D_n be the dihedral group of order 2n. Consider a continuous-time random walk on D_n driven by arbitrary symmetric rates whose support generates D_n. For p∈[1,∞], we say the pair (D_n,p) is rate-monotonic if for each fixed time t, the ℓ^p-distance between the random walk's distribution at time t and the uniform distribution is monotonically decreasing as a function of the rates. Lyons and White proved that (D_n,2) and (D_n,∞) are rate-monotonic. Somewhat counterintuitively, they found several pairs (D_n,p) with p∈[1,1.997]∪[2.001,3.999]∪[4.001,5.995] that are not rate-monotonic, and they asked whether any such pairs exist with p=4 or p=6. We resolve their question, proving that (D_n,2m) is rate-monotonic for all positive integers m and n. In fact, we prove a generalization of this result to a broader family of groups that includes generalized dihedral groups, dicyclic groups, and generalized quaternion groups. In the other direction, we prove that for every real p≥ 1 that is not an even integer, there exists a positive integer n such that (D_n,p) is not rate-monotonic. The results of this paper were formally verified in Lean by AxiomProver assuming standard literature.
ER -