Showing papers in "Kyungpook Mathematical Journal in 2019"

Curvature Properties of η-Ricci Solitons on Para-Kenmotsu Manifolds

Abstract: In the present paper, we study curvature properties of η-Ricci solitons on para-Kenmotsu manifolds. We obtain some results of η-Ricci solitons on para-Kenmotsu manifolds satisfying R(ξ,X).C = 0, R(ξ,X).M̃ = 0, R(ξ,X).P = 0, R(ξ,X).C̃ = 0 and R(ξ,X).H = 0, where C, M̃ , P , C̃ and H are a quasi-conformal curvature tensor, a M -projective curvature tensor, a pseudo-projective curvature tensor, and a concircular curvature tensor and conharmonic curvature tensor, respectively.

On a Symbolic Method for Fully Inhomogeneous Boundary Value Problems

Abstract: This paper presents a symbolic method for solving a boundary value problem with inhomogeneous Stieltjes boundary conditions over integro-differential algebras. The proposed symbolic method includes computing the Green’s operator as well as the Green’s function of the given problem. Examples are presented to illustrate the proposed symbolic method.

An Application of Absolute Matrix Summability using Almost Increasing and delta-quasi-monotone Sequences

Abstract: A positive sequence (vn) is said to be almost increasing if there exists a positive increasing sequence (cn) and two positive constants K and L such that Kcn ≤ vn ≤ Lcn (see [1]). A sequence (yn) is said to be δ-quasi-monotone, if yn → 0, yn > 0 ultimately and ∆yn ≥ −δn, where ∆yn=yn − yn+1 and δ = (δn) is a sequence of positive numbers (see [2]). Let ∑ an be a given infinite series with partial sums (sn). By (un) and (tn) we denote the n-th (C, 1) means of the sequences (sn) and (nan), respectively. The series ∑ an is said to be |C, 1|k summable, k ≥ 1, if (see [6], [8])

Weak and Strong Convergence of Hybrid Subgradient Method for Pseudomonotone Equilibrium Problems and Nonspreading- Type Mappings in Hilbert Spaces

Abstract: In this paper, we introduce a hybrid subgradient method for finding an element common to both the solution set of a class of pseudomonotone equilibrium problems, and the set of fixed points of a finite family of κ-strictly presudononspreading mappings in a real Hilbert space. We establish some weak and strong convergence theorems of the sequences generated by our iterative method under some suitable conditions. These convergence theorems are investigated without the Lipschitz condition for bifunctions. Our results complement many known recent results in the literature.

Hopf Hypersurfaces in Complex Two-plane Grassmannians with Generalized Tanaka-Webster Reeb-parallel Structure Jacobi Operator

Abstract: Regarding the generalized Tanaka-Webster connection, we considered a new notion of \(\mathfrak{D}^ \bot\)-parallel structure Jacobi operator for a real hypersurface in a complex two-plane Grassmannian G2(ℂm+2) and proved that a real hypersurface in G2(ℂm+2) with generalized Tanaka-Webster \(\mathfrak{D}^ \bot\)-parallel structure Jacobi operator is locally congruent to an open part of a tube around a totally geodesic quaternionic projective space ℍPn in G2(ℂm+2), where m = 2n.

Evolution of the First Eigenvalue of Weighted p-Laplacian along the Yamabe Flow

Abstract: Let M be an n-dimensional closed Riemannian manifold with metric g, dμ = e−φ(x)dν be the weighted measure and ∆p,φ be the weighted p-Laplacian. In this article we will study the evolution and monotonicity for the first nonzero eigenvalue problem of the weighted p-Laplace operator acting on the space of functions along the Yamabe flow on closed Riemannian manifolds. We find the first variation formula of it along the Yamabe flow. We obtain various monotonic quantities and give an example.

On the Boundedness of Marcinkiewicz Integrals on Variable Exponent Herz-type Hardy Spaces

Abstract: The aim of this paper is to prove that Marcinkiewicz integral operators are bounded from K̇ α(·),q(·) p(·) (R ) to K̇ α(·),q(·) p(·) (R ) when the parameters α(·), p(·) and q(·) satisfies some conditions. Also, we prove the boundedness of μ on variable Herz-type Hardy spaces HK̇ α(·),q(·) p(·) (R ).

Quasi 2-absorbing Submodules

Abstract: In this paper, we introduce the notion of quasi 2-absorbing submodules of modules over a commutative ring and obtain some basic properties of this class of modules.

Positive Solutions of Nonlinear Neumann Boundary Value Problems With Sign-Changing Green's Function

Abstract: Abstract. This paper is concerned with the existence of positive solutions of the nonlinear Neumann boundary value problems { u + a(t)u = λb(t)f(u), t ∈ (0, 1), u(0) = u(1) = 0, where a, b ∈ C[0, 1] with a(t) > 0, b(t) ≥ 0 and the Green’s function of the linear problem { u + a(t)u = 0, t ∈ (0, 1), u(0) = u(1) = 0 may change its sign on [0, 1]× [0, 1]. Our analysis relies on the Leray-Schauder fixed point theorem.

The Flatness Property of Local-cubically Hyponormal Weighted Shifts

Abstract: In this note we introduce a local-cubically hyponormal weighted shift of order θ with 0 ≤ θ ≤ π 2 , which is a new notion between cubic hyponormality and quadratic hyponormality of operators. We discuss the property of flatness for local-cubically hyponormal weighted shifts.