• Communications of the Korean Mathematical Society
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• v.26 no.4
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• pp.623-634
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• 2011

The object of the present paper is to study N(${\kappa}$)-quasi Einstein manifolds. Existence of N(${\kappa}$)-quasi Einstein manifolds are proved. Physical example of N(${\kappa}$)-quasi Einstein manifold is also given. Finally, Weyl-semisymmetric N(${\kappa}$)-quasi Einstein manifolds have been considered.

• Journal of the Chungcheong Mathematical Society
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• v.19 no.1
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• pp.37-47
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• 2006

In this paper we characterize the graphs whose inserted graphs are Hamiltonian, and we study the relationship between Hamiltonian graphs and inserted graphs. Also we prove that if a connected graph G contains at least 3 vertices then inserted graph of the square of G is Hamiltonian and if G contains at least 3 edges then the square of inserted graph of G is Hamiltonian.

• Communications of the Korean Mathematical Society
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• v.32 no.2
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• pp.401-416
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• 2017

The aim of this paper is to investigate locally ${\phi}-conformally$ symmetric almost Kenmotsu manifolds with its characteristic vector field ${\xi}$ belonging to some nullity distributions. Also, we give an example of a 5-dimensional almost Kenmotsu manifold such that ${\xi}$ belongs to the $(k,\;{\mu})^{\prime}$-nullity distribution and $h^{\prime}{\neq}0$.

• Kyungpook Mathematical Journal
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• v.46 no.3
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• pp.357-365
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• 2006

This paper is a sequel of our previous paper [1]. In this paper, we introduce the notions of regular ideal and partial ideal ($p$-ideal) in a ternary semiring and using these two notions we characterize regular ternary semiring.

• Kyungpook Mathematical Journal
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• v.49 no.3
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• pp.507-520
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• 2009

The object of the present paper is to study conformally at almost pseudo Ricci symmetric manifolds. The existence of a conformally at almost pseudo Ricci symmetric manifold with non-zero and non-constant scalar curvature is shown by a non-trivial example. We also show the existence of an n-dimensional non-conformally at almost pseudo Ricci symmetric manifold with vanishing scalar curvature.

• Journal of applied mathematics & informatics
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• v.13 no.1_2
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• pp.301-322
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• 2003

The paper considers two mutually independent pests in presence of their common predator and discusses their control biologically by release of additional predators and chemically by using non-selective non-residual pesticide. It also verifies the results by special choice of parameters.

• Journal of applied mathematics & informatics
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• v.28 no.5_6
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• pp.1379-1393
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• 2010

In this paper, a stage-structured predator prey model (stage structure on prey) with two discrete time delays has been discussed. The two discrete time delays occur due to maturation delay and gestation delay. Linear stability analysis for both non-delay as well as with delays reveals that certain thresholds have to be maintained for coexistence. Numerical simulation shows that the system exhibits Hopf bifurcation, resulting in a stable limit cycle.

• Communications of the Korean Mathematical Society
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• v.33 no.1
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• pp.261-272
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• 2018

The object of the present paper is to study some curvature properties of almost Kenmotsu manifolds with conformal Reeb foliation. Among others it is proved that an almost Kenmotsu manifold with conformal Reeb foliation is Ricci semisymmetric if and only if it is an Einstein manifold. Finally, we study Yamabe soliton in this manifold.

• Bulletin of the Korean Mathematical Society
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• v.56 no.1
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• pp.219-228
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• 2019

In this paper it is proved that on an almost $coK{\ddot{a}}hler$ 3-manifold M, (i) M is h-semisymmetric, (ii) the curvature condition $Q{\cdot}R=0$ and (iii) M is $coK{\ddot{a}}hler$ are equivalent.

• Kyungpook Mathematical Journal
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• v.61 no.4
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• pp.781-790
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• 2021

The goal of this paper is to characterize a class of almost Kenmotsu manifolds admitting *-conformal Ricci solitons. It is shown that if a (2n + 1)-dimensional (k, µ)'-almost Kenmotsu manifold M admits *-conformal Ricci soliton, then the manifold M is *-Ricci flat and locally isometric to ℍⁿ⁺¹(-4) × ℝⁿ. The result is also verified by an example.