Kenmotsu Contact Geometry Through the Lens of $\ast-\boldsymbolκ$-Ricci-Bourguignon Almost Solitons
Lavanya Kumar, Soumendu Roy
TL;DR
The paper introduces the $\ast-\boldsymbol{\kappa}$-Ricci-Bourguignon almost soliton on Kenmotsu manifolds, situating it within the framework of $\ast$-Ricci and Ricci–Bourguignon solitons. It derives the soliton equation $\boldsymbol{\kappa}\mathscr{L}_{\mathcal{V}}h+2\mathbb{T}^*-(2\Omega+\theta\mathcal{R}^*)h=0$ and proves that the star-scalar curvature satisfies $\mathcal{R}^*=\mathcal{R}+4n^2$, which together yield the crucial relation $\Omega=\frac{\theta(\mathcal{R}+4n^2)}{2}$ when $\mathcal{V}$ is the Reeb field. The work further analyzes gradient solitons via a Poisson equation $\Delta(u)= -\frac{(\mathcal{R}+4n^2)}{\boldsymbol{\kappa}}\left[1+\frac{\theta(2n+1)}{2}\right]-\frac{\Omega}{\boldsymbol{\kappa}}(2n+1)$ and identifies special cases $\theta\in\{0,1,2\}$ corresponding to $\ast$-$\boldsymbol{\kappa}$-RBS, $\ast$-RB solitons, and $\ast$-$\boldsymbol{\kappa}$-Einsteinian solitons. The role of torse-forming vector fields is developed, giving explicit $\Omega$-formulas and a classification of torse-generating types that yield $\boldsymbol{\eta}$-Einsteinian structures under suitable conditions. An explicit 5D Kenmotsu example demonstrates the construction and confirms the parameter regimes for contracting/steady/growing solitons, highlighting practical realizations of the theory.
Abstract
This paper focuses on the study of the newly introduced $\ast-\boldsymbolκ$-Ricci-Bourguignon almost soliton pertaining to Kenmotsu structure manifolds. Our analysis concerns the characteristics of this soliton and derive the scalar curvature for a Kenmotsu manifold admitting such a structure. Further, we formulate the corresponding vector fields under the assumption that the manifold supports a $\ast-\boldsymbolκ-$Ricci-Bourguignon soliton. Additionally, we explore applications involving torse-forming vector fields within the framework of the $\ast-\boldsymbolκ-$Ricci-Bourguignon almost soliton on Kenmotsu structure manifolds. To support the theoretical findings, we provide a concrete illustration belonging to a $\ast-\boldsymbolκ-$Ricci-Bourguignon almost soliton in a 5D Kenmotsu structure manifold.
