PreprintCC BY 4.0arXiv
Hit-and-Run Mixes as Fast as the Ball Walk
Abstract
Let K⊂ℝn be an isotropic convex body. We prove that the hit-and-run walk, started from any M-warm distribution, reaches total-variation distance ε from the uniform distribution on K in O (n2ψn−2log3(M/ε)) steps, where ψn−1 is the Kannan-Lovász-Simonovits (KLS) constant. Up to logarithmic factors, this matches the best-known warm-start mixing time for the ball walk. Chen and Eldan [Discrete Comput. Geom. 2026] obtained the same n2ψn−2 dependence for hit-and-run, but with polynomial dependence on M/ε. Our result improves that polynomial dependence to a polylogarithmic one, fully resolving their open question about warm-start mixing of hit-and-run in isotropic convex bodies.
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BibTeX
@misc{zhang2026hitandrun,
title = {{Hit-and-Run Mixes as Fast as the Ball Walk}},
author = {Ruizhe Zhang},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2608.13487},
eprint = {2608.13487},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2608.13487},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Hit-and-Run Mixes as Fast as the Ball Walk
AU - Ruizhe Zhang
PY - 2026
DA - 2026/09/05
PB - arXiv
DO - 10.48550/arxiv.2608.13487
UR - https://arxiv.org/abs/2608.13487
AB - Let K⊂ℝ^n be an isotropic convex body. We prove that the hit-and-run walk, started from any M-warm distribution, reaches total-variation distance ε from the uniform distribution on K in O (n^2ψ_n^−2log^3(M/ε)) steps, where ψ_n^−1 is the Kannan-Lovász-Simonovits (KLS) constant. Up to logarithmic factors, this matches the best-known warm-start mixing time for the ball walk. Chen and Eldan [Discrete Comput. Geom. 2026] obtained the same n^2ψ_n^−2 dependence for hit-and-run, but with polynomial dependence on M/ε. Our result improves that polynomial dependence to a polylogarithmic one, fully resolving their open question about warm-start mixing of hit-and-run in isotropic convex bodies.
ER -