PreprintCC BY 4.0arXiv
The Zaporozhets-Tarasov Conjecture on Mean Distances
Abstract
For a convex body K ⊂ ℝd let Δ(K) be the expected distance between two independent uniform points of K, and let θ(K) be the corresponding expectation for normalized surface measure on ∂ K. The Zaporozhets-Tarasov conjecture asserts Δ(K) ≤ θ(K). We prove this conjecture in case d=2. In addition, we give a six-vertex convex polytope in ℝ3 for which the reverse strict inequality holds, and obtain counterexamples in every dimension d ≥ 3 by taking products with segments. Finally, we show that θ(K)> perK/6 for every planar convex body.
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BibTeX
@misc{shen2026zaporozhetstarasov,
title = {{The Zaporozhets-Tarasov Conjecture on Mean Distances}},
author = {Eric Shen},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2608.06470},
eprint = {2608.06470},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2608.06470},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - The Zaporozhets-Tarasov Conjecture on Mean Distances
AU - Eric Shen
PY - 2026
DA - 2026/09/03
PB - arXiv
DO - 10.48550/arxiv.2608.06470
UR - https://arxiv.org/abs/2608.06470
AB - For a convex body K ⊂ ℝ^d let Δ(K) be the expected distance between two independent uniform points of K, and let θ(K) be the corresponding expectation for normalized surface measure on ∂ K. The Zaporozhets-Tarasov conjecture asserts Δ(K) ≤ θ(K). We prove this conjecture in case d=2. In addition, we give a six-vertex convex polytope in ℝ^3 for which the reverse strict inequality holds, and obtain counterexamples in every dimension d ≥ 3 by taking products with segments. Finally, we show that θ(K)> perK/6 for every planar convex body.
ER -