Spectral Monotonicity under Leaf Attachment and Limiting Behavior in Discrete Einstein Trees

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 Let $R_T$ be the Ricci matrix of a finite tree $T$ introduced in \cite{BaiChengHua2026}, the largest eigenvalue $λ_{\max}(R_T)$ determines the sign of a discrete Einstein metric curvature on the tree. This paper investigates the asymptotic behavior of the sequence $λ_k = λ_{\max}(R_{T_k})$ obtained by repeatedly adding pendant edges at a fixed vertex. We prove that $λ_k$ converges to a limit $λ_\infty$ that depends only on the local branch data of $T$, and establish a first-order asymptotic expansion: \[ λ_k = λ_\infty + \fracα{d+k} + O\!\left(\frac{1}{(d+k)^2}\right), \] where $d$ is the degree of the original vertex, and the coefficient $α$ is given by a spectral projection. As a corollary, when $α\neq 0$, $λ_k$ is eventually strictly monotonic (increasing or decreasing). This theory reveals the fine influence of local leaf addition on the global spectrum.
format Preprint
id arxiv_https___arxiv_org_abs_2605_23379
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Spectral Monotonicity under Leaf Attachment and Limiting Behavior in Discrete Einstein Trees
Bai, Shuliang
Cheng, Haoxuan
Hua, Bobo
Differential Geometry
Spectral Theory
53C21
Let $R_T$ be the Ricci matrix of a finite tree $T$ introduced in \cite{BaiChengHua2026}, the largest eigenvalue $λ_{\max}(R_T)$ determines the sign of a discrete Einstein metric curvature on the tree. This paper investigates the asymptotic behavior of the sequence $λ_k = λ_{\max}(R_{T_k})$ obtained by repeatedly adding pendant edges at a fixed vertex. We prove that $λ_k$ converges to a limit $λ_\infty$ that depends only on the local branch data of $T$, and establish a first-order asymptotic expansion: \[ λ_k = λ_\infty + \fracα{d+k} + O\!\left(\frac{1}{(d+k)^2}\right), \] where $d$ is the degree of the original vertex, and the coefficient $α$ is given by a spectral projection. As a corollary, when $α\neq 0$, $λ_k$ is eventually strictly monotonic (increasing or decreasing). This theory reveals the fine influence of local leaf addition on the global spectrum.
title Spectral Monotonicity under Leaf Attachment and Limiting Behavior in Discrete Einstein Trees
topic Differential Geometry
Spectral Theory
53C21
url https://arxiv.org/abs/2605.23379