dorsal/arxiv
View SchemaConvex combination of first and second eigenvalues of trees
| Authors | Hitesh Kumar, Bojan Mohar, Shivaramakrishna Pragada, Hanmeng Zhan |
|---|---|
| Categories | |
| ArXiv ID | 2601.10036vv1 |
| URL | https://arxiv.org/abs/2601.10036 |
| License | http://creativecommons.org/licenses/by/4.0/ |
Abstract
For a graph $G$, let $\lambda_1(G)$ and $\lambda_2(G)$ denote the largest and the second largest adjacency eigenvalue of $G$. The sum $\lambda_1(G) + \lambda_2(G)$ is called the \emph{spectral sum} of $G$. We investigate the spectral sum of trees of order $n$ and determine the extremal trees that achieve maximum/minimum. Moreover, for any $\alpha \in [0,1]$, we determine the extremal trees which maximize the convex combination $\alpha \lambda_1 + (1-\alpha)\lambda_2$ in the class of $n$-vertex trees.
{
"annotation_id": "83c04dbb-5d93-480f-bdd7-efb7d0af54ec",
"date_created": "2026-02-17T05:53:23.555000Z",
"date_modified": "2026-02-17T05:53:23.555000Z",
"file_hash": "915e54393753069530a9e26a695b5803ca134fed4bf90b9a40d92dfcaeeaeee3",
"private": false,
"record": {
"abstract": "For a graph $G$, let $\\lambda_1(G)$ and $\\lambda_2(G)$ denote the largest and the second largest adjacency eigenvalue of $G$. The sum $\\lambda_1(G) + \\lambda_2(G)$ is called the \\emph{spectral sum} of $G$. We investigate the spectral sum of trees of order $n$ and determine the extremal trees that achieve maximum/minimum. Moreover, for any $\\alpha \\in [0,1]$, we determine the extremal trees which maximize the convex combination $\\alpha \\lambda_1 + (1-\\alpha)\\lambda_2$ in the class of $n$-vertex trees.",
"arxiv_id": "2601.10036",
"authors": [
"Hitesh Kumar",
"Bojan Mohar",
"Shivaramakrishna Pragada",
"Hanmeng Zhan"
],
"categories": [
"math.CO"
],
"license": "http://creativecommons.org/licenses/by/4.0/",
"title": "Convex combination of first and second eigenvalues of trees",
"url": "https://arxiv.org/abs/2601.10036",
"version": "v1"
},
"schema_id": "dorsal/arxiv",
"source": {
"execution_id": "ae460906-0b4d-45dd-96eb-2247a011b135",
"id": "arXiv Dataset",
"type": "Model",
"variant": "snapshot-2026-01-17",
"version": "0.1.0"
},
"user_id": 1000002
}