Edge Subdivision and the Perron Eigenvalue of Tree Ricci Matrices

Fuente: arXiv
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Main Authors: Bai, Shuliang, Cheng, Haoxuan, Hua, Bobo
Format: Preprint
Published: 2026
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author Bai, Shuliang
Cheng, Haoxuan
Hua, Bobo
author_facet Bai, Shuliang
Cheng, Haoxuan
Hua, Bobo
contents The Ricci matrix $R_T$ of a finite tree encodes its discrete Einstein metrics via the Perron eigenvector, with Lin-Lu-Yau's Ollivier Ricci curvature: $κ= -λ_{\max}(R_T)$. We show that edge subdivision, the natural operation of lengthening a tree, can decrease, preserve, or increase $λ_{\max}$. Compressing each branch into a scalar feedback function via the Schur complement reduces the spectral problem to a one-dimensional Chebyshev equation. We obtain an exact one-step trichotomy, a scalar transmission equation for arbitrary length, and the long-chain limit. Examples on double stars, including an asymmetric case where subdivision strictly increases $λ_{\max}$, illustrate the theory.
format Preprint
id arxiv_https___arxiv_org_abs_2605_30949
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Edge Subdivision and the Perron Eigenvalue of Tree Ricci Matrices
Bai, Shuliang
Cheng, Haoxuan
Hua, Bobo
Differential Geometry
Spectral Theory
53C21
The Ricci matrix $R_T$ of a finite tree encodes its discrete Einstein metrics via the Perron eigenvector, with Lin-Lu-Yau's Ollivier Ricci curvature: $κ= -λ_{\max}(R_T)$. We show that edge subdivision, the natural operation of lengthening a tree, can decrease, preserve, or increase $λ_{\max}$. Compressing each branch into a scalar feedback function via the Schur complement reduces the spectral problem to a one-dimensional Chebyshev equation. We obtain an exact one-step trichotomy, a scalar transmission equation for arbitrary length, and the long-chain limit. Examples on double stars, including an asymmetric case where subdivision strictly increases $λ_{\max}$, illustrate the theory.
title Edge Subdivision and the Perron Eigenvalue of Tree Ricci Matrices
topic Differential Geometry
Spectral Theory
53C21
url https://arxiv.org/abs/2605.30949