• Bulletin of the Korean Mathematical Society
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• v.45 no.4
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• pp.621-629
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• 2008

Let R be a prime ring of characteristic different from 2, C the extended centroid of R, and $\delta$ a generalized derivations of R. If [[$\delta(x)$, x], $\delta(x)$] = 0 for all $x\;{\in}\;R$ then either R is commutative or $\delta(x)\;=\;ax$ for all $x\;{\in}\;R$ and some $a\;{\in}\;C$. We also obtain some related result in case R is a Banach algebra and $\delta$ is either continuous or spectrally bounded.

• Kyungpook Mathematical Journal
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• v.50 no.1
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• pp.123-129
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• 2010

Molodtsov introduced the concept of soft sets, which can be seen as a new mathematical tool for dealing with uncertainty. In this paper, we initiate the study of soft BL-algebras by using the soft set theory. The notion of filteristic soft BL-algebras is introduced and some related properties are investigated.

• Honam Mathematical Journal
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• v.36 no.3
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• pp.555-568
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• 2014

On the basis of the theory of a falling shadow and fuzzy sets, the notion of a falling fuzzy BCI-commutative ideal of a BCI-algebra is introduced. Relations between falling fuzzy BCI-commutative ideals and falling fuzzy ideals are given. Relations between fuzzy BCI-commutative ideals and falling fuzzy BCI-commutative ideals are provided. Characterizations of a falling fuzzy BCI-commutative ideal are established, and conditions for a falling fuzzy (closed) ideal to be a falling fuzzy BCI-commutative ideal are considered.

• 제어로봇시스템학회:학술대회논문집
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• 1989.10a
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• pp.127-130
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• 1989

The redundant manipulator extends the application fields of classical nonredundant manipulators. In this paper, we propose Premultiplier Model that describes the static behavior of redundant manipulator. This model provides insight and intuition about algebra and physics related to redundant manipulators. Active operational space stiffness control of redundant manipulators is proved to be always unstable and we propose a technique, based on our methodology, to make stiffness control stable.

• Journal of the Chungcheong Mathematical Society
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• v.2 no.1
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• pp.81-90
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• 1989

Let $D:C^n(I){\longrightarrow}M$ be a derivation from the Banach algebra of n times continuously differentiable functions on an interval I into a Banach $C^n(I)$-module M. If D is continuous and D(z) is contained in the k-differential subspace, the image of D is contained in the k-differential subspace. The question of when the image of a derivation is contained in the k-differential subspace is discussed.

• Journal of applied mathematics & informatics
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• v.6 no.1
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• pp.303-307
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• 1999

Let A and B be two strictly dense Banach Algebras on X and Y respectively where X and Y are Banach space. We give some conditions under which full spectrum preserving linear mappings from A into B Jordan morphisms and X is homomorphic to Y.

• Communications of the Korean Mathematical Society
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• v.28 no.3
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• pp.535-558
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• 2013

The purpose of this paper is to prove that the noncommutative version of the Singer-Wermer Conjecture is affirmative under certain conditions. Let A be a noncommutative Banach algebra. Suppose there exists a continuous linear Jordan derivation $D:A{\rightarrow}A$ such that $D(x)^3[D(x),x]{\in}rad(A)$ for all $x{\in}A$. In this case, we show that $D(A){\subseteq}rad(A)$.

• Kyungpook Mathematical Journal
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• v.55 no.2
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• pp.251-258
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• 2015

Let $\mathcal{A}$ be a unital $C^*$-algebra, a, x and y are elements in $\mathcal{A}$. In this paper, we present the expression of the Moore-Penrose inverse and the group inverse of a-$xy^*$ under the conditions $x=aa^+x,y^*=y^*a^+a$, respectively.

• Journal for History of Mathematics
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• v.11 no.2
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• pp.1-7
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• 1998

Lee, Sang-Hyuk(1810-\ulcorner) said that Cha-Geun-Bang means algebra come from the West. In the chapter 'Che-Lyu' of the second volume of his book Cha-Geun-Bang-Mong-Gu, he gave the list of questions which could be expressed by the equation of one variable and explained the solution for them. All questions were formulated by equations of degree 2, 3, 4 which have terms on both sides of equal sign and they mostly have natural number solutions. The explanation of each question describes the procedure to make the equation in detail, but only presents the solution with few step to solve.

• Research in Mathematical Education
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• v.1 no.1
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• pp.1-5
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• 1997

We discuss some aspects of mathematics for teachers such as algebra for teachers, geometry for teachers, statistics for teachers, etc., which can be taught in teacher preparation courses. Mathematics for teachers should consider the followings: (a) Various solutions for a problem, (b) The dynamics of a problem introduced by change of condition, (c) Relationship of mathematics to real life, (d) Mathematics history and historical issues, (e) The difference between pure mathematics and pedagogical mathematics, (f) Understanding of the theoretical backgrounds, and (g) Understanding advanced mathematics.