Cone Conditions for the Curvature Operator of the Second Kind on Einstein Manifolds

Fuente: arXiv
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Autores principales: Cheng, Haiqing, Wang, Kui
Formato: Preprint
Publicado: 2026
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author Cheng, Haiqing
Wang, Kui
author_facet Cheng, Haiqing
Wang, Kui
contents In this note, we study Einstein manifolds whose curvature operator of the second kind $\mathring{R}$ satisfies the cone condition \[ α^{-1}\big(\sum_{i=1}^{[α]} λ_i+ (α- [α] ) λ_{[α] + 1} \big) \ge -θ\barλ \] for some real number $α\in [1, (n+2)(n-1)/2)$. Here $[α] :=\max\{ m \in \mathbb{Z}: m \leq α\}$, $θ>-1$ and $λ_1 \le \cdots \le λ_{(n+2)(n-1)/2}$ are the eigenvalues of $\mathring{R}$ and $\barλ$ is their average. The main result states that any closed Einstein manifold of dimension $n \ge 4$ with $\mathring{R}$ satisfies the cone condition is flat or a round sphere. These results generalize recent works corresponding to $α\in \mathbb Z_+$ of the authors \cite{CW24-1,CW25-2} and Fu-Lu \cite{FL25}.
format Preprint
id arxiv_https___arxiv_org_abs_2601_06556
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Cone Conditions for the Curvature Operator of the Second Kind on Einstein Manifolds
Cheng, Haiqing
Wang, Kui
Differential Geometry
53C20, 53C24, 53C25
In this note, we study Einstein manifolds whose curvature operator of the second kind $\mathring{R}$ satisfies the cone condition \[ α^{-1}\big(\sum_{i=1}^{[α]} λ_i+ (α- [α] ) λ_{[α] + 1} \big) \ge -θ\barλ \] for some real number $α\in [1, (n+2)(n-1)/2)$. Here $[α] :=\max\{ m \in \mathbb{Z}: m \leq α\}$, $θ>-1$ and $λ_1 \le \cdots \le λ_{(n+2)(n-1)/2}$ are the eigenvalues of $\mathring{R}$ and $\barλ$ is their average. The main result states that any closed Einstein manifold of dimension $n \ge 4$ with $\mathring{R}$ satisfies the cone condition is flat or a round sphere. These results generalize recent works corresponding to $α\in \mathbb Z_+$ of the authors \cite{CW24-1,CW25-2} and Fu-Lu \cite{FL25}.
title Cone Conditions for the Curvature Operator of the Second Kind on Einstein Manifolds
topic Differential Geometry
53C20, 53C24, 53C25
url https://arxiv.org/abs/2601.06556