• Korean Journal of Mathematics
• /
• 제27권1호
• /
• pp.131-140
• /
• 2019

In this paper we have introduced the concept of pseudo-metric which we induced from a pseudo-valuation on KU-algebras and investigated the relationship between pseudo-valuations and ideals of KU-algebras. Conditions for a real-valued function to be a pseudo-valuation on KU-algebras are provided.

• Kyungpook Mathematical Journal
• /
• 제51권4호
• /
• pp.457-468
• /
• 2011

We consider pseudo-symmetric and Ricci generalized pseudo-symmetric N(${\kappa}$) contact metric manifolds. We also consider N(${\kappa}$)-contact metric manifolds satisfying the condition $S{\cdot}R$ = 0 where R and S denote the curvature tensor and the Ricci tensor respectively. Finally we give some examples.

• 대한수학회보
• /
• 제61권3호
• /
• pp.867-873
• /
• 2024

A pseudo-Riemannian solvmanifold is a solvable Lie group endowed with a left invariant pseudo-Riemannian metric. In this short note, we investigate the nilpotency of the Ricci operator of pseudo-Riemannian solvmanifolds. We focus on a special class of solvable Lie groups whose Lie algebras can be expressed as a one-dimensional extension of a nilpotent Lie algebra ℝD⋉n, where D is a derivation of n whose restriction to the center of n has at least one real eigenvalue. The main result asserts that every solvable Lie group belonging to this special class admits a left invariant pseudo-Riemannian metric with nilpotent Ricci operator. As an application, we obtain a complete classification of three-dimensional solvable Lie groups which admit a left invariant pseudo-Riemannian metric with nilpotent Ricci operator.

• 대한수학회논문집
• /
• 제35권4호
• /
• pp.1269-1281
• /
• 2020

In this article, we show that a pseudo-Hermitian magnetic curve in a normal almost contact metric 3-manifold equipped with the canonical affine connection ${\hat{\nabla}}^t$ is a slant helix with pseudo-Hermitian curvature ${\hat{\kappa}}={\mid}q{\mid}\;sin\;{\theta}$ and pseudo-Hermitian torsion ${\hat{\tau}}=q\;cos\;{\theta}$. Moreover, we prove that every pseudo-Hermitian magnetic curve in normal almost contact metric 3-manifolds except quasi-Sasakian 3-manifolds is a slant helix as a Riemannian geometric sense. On the other hand we will show that a pseudo-Hermitian magnetic curve γ in a quasi-Sasakian 3-manifold M is a slant curve with curvature κ = |(t - α) cos θ + q| sin θ and torsion τ = α + {(t - α) cos θ + q} cos θ. These curves are not helices, in general. Note that if the ambient space M is an α-Sasakian 3-manifold, then γ is a slant helix.

• 호남수학학술지
• /
• 제32권2호
• /
• pp.217-226
• /
• 2010

Using the Bu$\c{s}$neag's model ([1, 2, 3]), the notion of pseudo-valuations (valuations) on a ${\mathbf{BCK/BCI}}$-algebra is introduced, and a pseudo-metric is induced by a pseudo-valuation on ${\mathbf{BCK/BCI}}$-algebras. Based on the notion of (pseudo) valuation, we show that the binary operation in ${\mathbf{BCK/BCI}}$-algebras is uniformly continuous.

• 호남수학학술지
• /
• 제36권4호
• /
• pp.853-862
• /
• 2014

In this paper, we define a metric induced by the Bergman Kernel and prove a property that the metric has under any biholomorphic mapping.

• 충청수학회지
• /
• 제33권2호
• /
• pp.287-292
• /
• 2020

In this paper, we prove that a distal homeomorphism f of a compact connected metric space X does not have the eventual pseudo orbit tracing property.

• 응용통계연구
• /
• 제28권6호
• /
• pp.1171-1180
• /
• 2015

다차원척도법(multidimensional scaling)이란 개체간의 비유사성을 저차원 공간에 기하적으로 나타내려는 다변량 분석의 그래프적 기법이다. 일반적으로 다차원척도법은 계량형 다차원척도법과 비계량형 다차원척도법으로 분류할 수 있는데, 계량형 다차원척도법은 양적자료에 적용하게 된다. 그러나 이를 통해서는 개체들에 대한 군집화 정보만을 파악할 수 있으며, 개별 군집의 특징을 파악하기 위해서는 가상점(pseudo-points)을 활용한 변수들의 정보에 대한 추가적인 표현이 요구된다. 이러한 이유로 Gower (1992)는 연속형 변수에 대한 가상점들의 궤적을 표현함으로서 계량형 다차원척도법의 공간 상에 변수 정보를 나타내는 '대체법(replacement method)'을 제안한 바 있다. 그러나 이진수 자료는 계량형 다차원척도법을 적용할 수 있음에도 불구하고 대체법을 적용하면 가상점의 궤적을 표현할 수 없다. 따라서 본 연구에서는 이진수 자료에 대한 다차원척도법의 공간 상에 가상점을 이용하여 변수 정보를 표현하는 '분할법(partition method)'을 제안하려한다. 분할법은 0과 1의 비율을 모두 고려하여 가상점을 결정한다. 따라서 분할법에 의한 가상점을 활용한 계량형 다차원척도법을 통해 이진수 자료에서 변수와 개체간의 관계를 파악할 수 있게 해준다.

• Kyungpook Mathematical Journal
• /
• 제55권3호
• /
• pp.731-739
• /
• 2015

The object of the present paper is to characterize a Riemannian manifold admitting a type of semi-symmetric non-metric connection.

• 한국경영과학회지
• /
• 제19권1호
• /
• pp.41-52
• /
• 1994

Imprecision of evaluation or lack of prior information about preference can be an obstacle for decision maker in representing his strict preference. Therefore, fuzziness of preference can take place, and in addition, intransitivity or incomparability of preference becomes the critical difficulty in making complete preorder of alternatives. In order to get better solution and to improve practical usufulness, MCDM should be established as a pseudo-criterion model that include fuzzy preference. In this paper, we suggest a pseudo-criterion model that can make complete preorder of alternatives by metric distance measure.