PreprintCC BY 4.0arXiv
Convexity of a ratio function involving polygamma functions and monotonicity of the sectional curvature of the Fisher--Rao manifold
Abstract
This paper proves that the sectional curvature of the Fisher--Rao manifold of beta distributions, restricted to the diagonal, is strictly decreasing. The proof is based on a general convexity lemma for ratios involving positive decreasing functions and is applied to a quotient of polygamma functions.
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BibTeX
@misc{qi2026convexity,
title = {{Convexity of a ratio function involving polygamma functions and monotonicity of the sectional curvature of the Fisher--Rao manifold}},
author = {Feng Qi},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2609.10628},
eprint = {2609.10628},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.10628},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Convexity of a ratio function involving polygamma functions and monotonicity of the sectional curvature of the Fisher--Rao manifold
AU - Feng Qi
PY - 2026
DA - 2026/10/28
PB - arXiv
DO - 10.48550/arxiv.2609.10628
UR - https://arxiv.org/abs/2609.10628
AB - This paper proves that the sectional curvature of the Fisher--Rao manifold of beta distributions, restricted to the diagonal, is strictly decreasing. The proof is based on a general convexity lemma for ratios involving positive decreasing functions and is applied to a quotient of polygamma functions.
ER -