The multiplicity of eigenvalues of nonnegative weakly irreducible tensors and uniform hypergraphs

Fuente: arXiv
Saved in:
Bibliographic Details
Main Author: Fan, Yi-Zheng
Format: Preprint
Published: 2024
Subjects:
Online Access:
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866913595213742080
author Fan, Yi-Zheng
author_facet Fan, Yi-Zheng
contents Hu and Ye conjectured that for a $k$-th order and $n$-dimensional tensor $\mathcal{A}$ with an eigenvalue $λ$ and the corresponding eigenvariety $\mathcal{V}_λ(\mathcal{A})$, $$\mathrm{am}(λ) \ge \sum_{i=1}^κ\mathrm{dim}(V_i)(k-1)^{\mathrm{dim}(V_i)-1},$$ where $\mathrm{am}(λ)$ is the algebraic multiplicity of $λ$, and $V_1,\ldots,V_κ$ are all irreducible components of $\mathcal{V}_λ(\mathcal{A})$. In this paper, we prove that if $\mathcal{A}$ is a nonnegative weakly irreducible tensor with spectral radius $ρ$, then $\mathrm{am}(λ) \ge |\mathbb{V}_λ(\mathcal{A})|$ for all eigenvalues $λ$ of $\mathcal{A}$ with modulus $ρ$, where $\mathbb{V}_λ(\mathcal{A})$ is the projective eigenvariety of $\mathcal{A}$ associated with $λ$. Consequently we confirm Hu-Ye's conjecture for the above eigenvalues $λ$ of $\mathcal{A}$ and also the least H-eigenvalue of a weakly irreducible $Z$-tensor. We prove several equality cases in Hu-Ye's conjecture for the eigenvalues of the adjacency tensor or Laplacian tensor of uniform hypergraphs.
format Preprint
id arxiv_https___arxiv_org_abs_2410_20830
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle The multiplicity of eigenvalues of nonnegative weakly irreducible tensors and uniform hypergraphs
Fan, Yi-Zheng
Combinatorics
Primary 15A18, 13P15, Secondary 05C65, 13H15
Hu and Ye conjectured that for a $k$-th order and $n$-dimensional tensor $\mathcal{A}$ with an eigenvalue $λ$ and the corresponding eigenvariety $\mathcal{V}_λ(\mathcal{A})$, $$\mathrm{am}(λ) \ge \sum_{i=1}^κ\mathrm{dim}(V_i)(k-1)^{\mathrm{dim}(V_i)-1},$$ where $\mathrm{am}(λ)$ is the algebraic multiplicity of $λ$, and $V_1,\ldots,V_κ$ are all irreducible components of $\mathcal{V}_λ(\mathcal{A})$. In this paper, we prove that if $\mathcal{A}$ is a nonnegative weakly irreducible tensor with spectral radius $ρ$, then $\mathrm{am}(λ) \ge |\mathbb{V}_λ(\mathcal{A})|$ for all eigenvalues $λ$ of $\mathcal{A}$ with modulus $ρ$, where $\mathbb{V}_λ(\mathcal{A})$ is the projective eigenvariety of $\mathcal{A}$ associated with $λ$. Consequently we confirm Hu-Ye's conjecture for the above eigenvalues $λ$ of $\mathcal{A}$ and also the least H-eigenvalue of a weakly irreducible $Z$-tensor. We prove several equality cases in Hu-Ye's conjecture for the eigenvalues of the adjacency tensor or Laplacian tensor of uniform hypergraphs.
title The multiplicity of eigenvalues of nonnegative weakly irreducible tensors and uniform hypergraphs
topic Combinatorics
Primary 15A18, 13P15, Secondary 05C65, 13H15
url https://arxiv.org/abs/2410.20830