• 대한수학회지
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• 제58권4호
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• pp.799-817
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• 2021

In this paper, we investigate the normal and complex symmetric weighted composition operators W_𝜓,𝜑 on the Hardy space H²(𝔻). Firstly, we give the explicit conditions of weighted composition operators to be normal and complex symmetric with respect to conjugations 𝒞₁ and 𝒞₂ on H²(𝔻), respectively. Moreover, we particularly investigate the weighted composition operators W_𝜓,𝜑 on H²(𝔻) which are normal and complex symmetric with respect to conjugations 𝓙, 𝒞₁ and 𝒞₂, respectively, when 𝜑 has an interior fixed point, 𝜑 is of hyperbolic type or parabolic type.

• 대한수학회논문집
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• 제28권1호
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• pp.143-154
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• 2013

We introduce a subclass $S_s^{({\kappa})}$(A,B) (-1 ${\leq}$ B < A ${\leq}$ 1) of functions which are analytic in the open unit disk and close-to-convex with respect to ${\kappa}$-symmetric points. We give some coefficient inequalities, integral representations and invariance properties of functions belonging to this class.

• Korean Journal of Mathematics
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• 제29권4호
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• pp.705-714
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• 2021

In the present paper, we study 𝜂-Ricci solitons on para-Kenmotsu manifolds with Codazzi type of the Ricci tensor. We study 𝜂-Ricci solitons on para-Kenmotsu manifolds with cyclic parallel Ricci tensor. We also study 𝜂-Ricci solitons on 𝜑-conformally semi-symmetric, 𝜑-Ricci symmetric and conformally Ricci semi-symmetric para-Kenmotsu manifolds. Finally, we construct an example of a three-dimensional para-Kenmotsu manifold which admits 𝜂-Ricci solitons.

• Korean Journal of Mathematics
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• 제27권1호
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• pp.9-15
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• 2019

In this paper, we study a type of Riemannian manifold, namely quasi Ricci symmetric manifold. Among others, we show that the scalar curvature of a quasi Ricci symmetric manifold is constant. In addition if the manifold is Einstein, then its Ricci tensor is zero. Also we prove that if the associated vector field of a quasi Ricci symmetric manifold is either recurrent or concurrent, then its Ricci tensor is zero.

• 한국정밀공학회지
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• 제13권1호
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• pp.69-77
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• 1996

To design high-effective profile in screw rotor profile using in screw compressor, we design the symmetric type changing the number of lobes and the non-symmetric type changing the neighbourhood of the top point of lobe. Then, we calculated the performance value of profile according to the scale of these non-symmetric's wrap angle. We had the results as follows. 1. About the non-symmetric case, the larger a wrap angle is the shorter seal line is and the smaller blow hole is, thus we know what the large wrap angle profile is better than the small one. 2. We know what the non-symmetric profile is better than the symmetric profile in the result of the compare of seal line's length, blow hole's area, volume curve. 3. About the non-symmetric case, the deformation of the neighbourhood of lobe's top point of the rotor profile has a large effect upon the increase of performance because the length of seal line became short and the area of blow hole is small.

• 대한기계학회논문집
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• 제12권3호
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• pp.497-504
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• 1988

본 연구에서는 트랙션이 없는 커스프 균열에 적용한 방법을 확장하여 무한대 에서 균일열유동을 받는 무한체내에 하이포사이클로이드형(hypocycloid type), 대칭이 기형(symmetric airfoil type), 대칭입술형(symmetric lip type) 강체 함유물이 존재 하고 그 표면은 단열되거나 상대온도가 영으로 주어지는 경우에 대해서 열응력세기계 수(thermal stress intensity factor이하에서 TSIF로 표기함)를 유도하고자 한다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2008년도 추계학술대회 논문집
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• pp.3-4
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• 2008

• East Asian mathematical journal
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• 제38권5호
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• pp.611-616
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• 2022

This paper considers the Jacobian variety of a hyperelliptic curve over a finite field with mixed symmetric formal type. We present the Newton polygon of the characteristic polynomial of the Frobenius endomorphism of the Jacobian variety. It gives a useful tool for finding the local decomposition of the Jacobian variety into isotypic components.

• Journal of applied mathematics & informatics
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• 제32권1_2호
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• pp.153-159
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• 2014

In this paper, we introduce a pair of higher-order symmetric dual models/problems. Weak, strong and converse duality theorems for this pair are established under the assumption of higher-order invexity. Moreover, self duality theorem is also discussed.

• 호남수학학술지
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• 제42권3호
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• pp.461-476
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• 2020

The present study initially identify the generalized symmetric connections of type (α, β), which can be regarded as more generalized forms of quarter and semi-symmetric connections. The quarter and semi-symmetric connections are obtained respectively when (α, β) = (1, 0) and (α, β) = (0, 1). Taking that into account, a new generalized symmetric metric connection is attained on Lorentzian para-Sasakian manifolds. In compliance with this connection, some results are obtained through calculation of tensors belonging to Lorentzian para-Sasakian manifold involving curvature tensor, Ricci tensor and Ricci semi-symmetric manifolds. Finally, we consider CR-submanifolds admitting a generalized symmetric metric connection and prove many interesting results.