An algorithm for approximating the metric projection onto a superelliptic disk
Abstract
We study conditions under which the metric projection onto a strictly convex body can be approximated by the projections onto polygonal approximations (in the Hausdorff-Pompeiu sense) of the strictly convex body itself. We provide a necessary condition by proving that the union of all the vertices of the polygonal approximations must be dense in the boundary of that set. To showcase our result, given a superellipse (Lamé curve) of order p>1, we prove that a sequence of polygons obtained by radially projecting the torsion subgroup of the unit circle onto the superellipse, converges to the superellipse, in the Hausdorff-Pompeiu metric. Moreover, this leads to a globally convergent new algorithm useful in approximating the metric projection onto a superelliptic disk (the convex hull of a superellipse).
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BibTeX
@misc{fodor2026algorithm,
title = {{An algorithm for approximating the metric projection onto a superelliptic disk}},
author = {Valerian-Alin Fodor and Virgilius-Aurelian Minuta},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2605.24599},
eprint = {2605.24599},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2605.24599},
}
RIS
TY - UNPB
TI - An algorithm for approximating the metric projection onto a superelliptic disk
AU - Valerian-Alin Fodor
AU - Virgilius-Aurelian Minuta
PY - 2026
DA - 2026/10/04
PB - arXiv
DO - 10.48550/arxiv.2605.24599
UR - https://arxiv.org/abs/2605.24599
AB - We study conditions under which the metric projection onto a strictly convex body can be approximated by the projections onto polygonal approximations (in the Hausdorff-Pompeiu sense) of the strictly convex body itself. We provide a necessary condition by proving that the union of all the vertices of the polygonal approximations must be dense in the boundary of that set. To showcase our result, given a superellipse (Lamé curve) of order p>1, we prove that a sequence of polygons obtained by radially projecting the torsion subgroup of the unit circle onto the superellipse, converges to the superellipse, in the Hausdorff-Pompeiu metric. Moreover, this leads to a globally convergent new algorithm useful in approximating the metric projection onto a superelliptic disk (the convex hull of a superellipse).
ER -