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Distortion of Random Max Filters over Reflection Groups
Abstract
A max filter with Gaussian templates a1,…,aD is a G-invariant map Rd→RD, where G is a finite reflection group. As D→∞ its distortion converges a.s to the condition number of MG1/2, where MG is the second-moment matrix of a standard Gaussian vector moved into a fundamental chamber of G. We compute this limit exactly for the sign and dihedral groups, and show it grows as Θ(√d), Θ(d3/2) and Θ(k) for the sign, symmetric and dihedral groups of order 2k. The symmetric case bound uses a lower bound on the covariance of order statistics. For any finite G we also show that the infimum defining the optimal lower Lipschitz constant of a piecewise-linear G-invariant map is a minimum.
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BibTeX
@misc{tsoukanis2026distortion,
title = {{Distortion of Random Max Filters over Reflection Groups}},
author = {Efstratios Tsoukanis},
howpublished = {arXiv},
year = {2026},
month = nov,
doi = {10.48550/arxiv.2611.00305},
eprint = {2611.00305},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2611.00305},
}
RIS
TY - UNPB
TI - Distortion of Random Max Filters over Reflection Groups
AU - Efstratios Tsoukanis
PY - 2026
DA - 2026/11/01
PB - arXiv
DO - 10.48550/arxiv.2611.00305
UR - https://arxiv.org/abs/2611.00305
AB - A max filter with Gaussian templates a_1,…,a_D is a G-invariant map R^d→R^D, where G is a finite reflection group. As D→∞ its distortion converges a.s to the condition number of M_G^1/2, where M_G is the second-moment matrix of a standard Gaussian vector moved into a fundamental chamber of G. We compute this limit exactly for the sign and dihedral groups, and show it grows as Θ(√d), Θ(d^3/2) and Θ(k) for the sign, symmetric and dihedral groups of order 2k. The symmetric case bound uses a lower bound on the covariance of order statistics. For any finite G we also show that the infimum defining the optimal lower Lipschitz constant of a piecewise-linear G-invariant map is a minimum.
ER -