• Journal of the Korean Mathematical Society
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• v.31 no.4
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• pp.659-667
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• 1994

Let $H$ be a separable, infinite dimensional, complex Hilbert space and let $L(H)$ be the algebra of all bounded linear operators on $H$. A dual algebra is a subalgebra of $L(H)$ that contains the identity operator $I_H$ and is closed in the ultraweak operator topology on $L(H)$. Note that the ultraweak operator topology coincides with the weak topology on $L(H) (cf. [6]). Several functional analysists have studied the problem of solving systems of simultaneous equations in the predual of a dual algebra (cf. [3]). This theory is applied to the study of invariant subspaces and dilation theory, which are deeply related to the classes $A_{m,n}$ (that will be defined below) (cf. [3]). An abstract geometric criterion for dual algebras with property $(A_{\aleph_0}, {\aleph_0})$ was first given in [1].

• Kyungpook Mathematical Journal
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• v.32 no.3_spc
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• pp.415-420
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• 1992

• Journal for History of Mathematics
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• v.20 no.3
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• pp.167-180
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• 2007

In this study, we explored the role of analysis in the algebra development. For this, we classified ancient geometric analysis into an analysis by reduction and a Pappusian problematic analysis. this shows that both analyses have the function of reduction. Pappus' analysis consists of four steps; transformation, resolution, construction, demonstration. The transformation, by which conditions of given problem is transformed into other conditions which suggest a problem-solving, seems to be a kind of reduction. Mathematicians created new problems as a result of the reductional function of analysis, and became to see mathematics in the different view. An analytical thinking was a background at the birth of symbolic algebra, the reductional function of analysis played an important role in the development of symbolic algebra.

• Journal of the Korean Mathematical Society
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• v.45 no.3
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• pp.597-609
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• 2008

In this paper, we will consider certain amalgamated free product structure in crossed product algebras. Let M be a von Neumann algebra acting on a Hilbert space Hand G, a group and let ${\alpha}$ : G${\rightarrow}$ AutM be an action of G on M, where AutM is the group of all automorphisms on M. Then the crossed product $\mathbb{M}=M{\times}{\alpha}$ G of M and G with respect to ${\alpha}$ is a von Neumann algebra acting on $H{\bigotimes}{\iota}^2(G)$, generated by M and $(u_g)_g{\in}G$, where $u_g$ is the unitary representation of g on ${\iota}^2(G)$. We show that $M{\times}{\alpha}(G_1\;*\;G_2)=(M\;{\times}{\alpha}\;G_1)\;*_M\;(M\;{\times}{\alpha}\;G_2)$. We compute moments and cumulants of operators in $\mathbb{M}$. By doing that, we can verify that there is a close relation between Group Freeness and Amalgamated Freeness under the crossed product. As an application, we can show that if $F_N$ is the free group with N-generators, then the crossed product algebra $L_M(F_n){\equiv}M\;{\times}{\alpha}\;F_n$ satisfies that $$L_M(F_n)=L_M(F_{{\kappa}1})\;*_M\;L_M(F_{{\kappa}2})$$, whenerver $n={\kappa}_1+{\kappa}_2\;for\;n,\;{\kappa}_1,\;{\kappa}_2{\in}\mathbb{N}$.

• Journal of the Korea Society of Computer and Information
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• v.12 no.3
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• pp.251-258
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• 2007

With the increase of a web service technology, a new access control mechanism has developed for XML documents. As a result, as legacy access control systems, access control systems has become an active research topic. In this paper, we propose a methodology to translate access control policies for XML documents into formal specification language CSP. To do this, first, we introduce a method to translate a hierarchical access to XML documents using XPath language into CSP process algebra. Second, we explain a method to represent a XML schema as a formal model like automata. Third, we present a method for representing the semantics of access control policies such as the scope of rules and confliction resolution into a process algebra language. Finally, a CSP specification example of an XML schema and path expressions aye shown to illustrate the validity of our approach.

• Journal of Educational Research in Mathematics
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• v.11 no.1
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• pp.67-87
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• 2001

Variable concept plays a crucial role in understanding not only algebra itself but also school mathematics which is algebra-oriented. It solves as an essential means in applying mathematics to the real world because il enables us to describe varying phenomena in the real world. In this study, we examined some matters related to the learning of variable concept in school mathematics. In Particular, we discussed on the teaching of variable concept in the [7-first] stage of the 7th Mathematics Curriculum. We analysed the textbooks in the [7-first] stage and attempted to explain concretely the contents and teaching methods of variable concept which be taught in school mathematics. After reconsidering the practices on variable concept teaching, we pointed out the problems of formalistic teaching method and then proposed the direction in which variable concept teaching should go.

• Communications of the Korean Mathematical Society
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• v.21 no.1
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• pp.117-133
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• 2006

Cameron and Storvick discovered change of scale formulas for Wiener integrals of bounded functions in a Banach algebra S of analytic Feynman integrable functions on classical Wiener space. Yoo and Skoug extended these results to abstract Wiener space for a generalized Fresnel class $F_{A1,A2}$ containing the Fresnel class F(B) which corresponds to the Banach algebra S on classical Wiener space. In this paper, we present a change of scale formula for Wiener integrals of various functions on $B^2$ which need not be bounded or continuous.

• Journal of the Korean Mathematical Society
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• v.43 no.5
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• pp.951-965
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• 2006

In this paper, we study a topological mirror symmetry on noncommutative complex tori. We show that deformation quantization of an elliptic curve is mirror symmetric to an irrational rotation algebra. From this, we conclude that a mirror reflection of a noncommutative complex torus is an elliptic curve equipped with a Kronecker foliation.

• Bulletin of the Korean Mathematical Society
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• v.35 no.4
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• pp.727-739
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• 1998

We discuss dual algebras generated by a contraction and properties $({\mathbb}A_{m,n})$ which arise in the study of the problem of solving systems of the predual of a dual algebra. In particular, we study membership for the class ${\mathbb}A_1,{{\aleph}_0 }$. As some examples we consider dual algebras generated by a Jordan block.

• Communications of Mathematical Education
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• v.10
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• pp.125-141
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• 2000

현행 교육과정에서는 서로 만나는 두 직선의 둘레로 회전하여 얻는 곡면 즉 직원뿔을 꼭지점을 지나지 않는 평면으로 잘라 만들어지는 원추곡선 중에서 원을 제외한 포물선, 타원, 쌍곡선에 대한 시각적 직관적 개념 형성 지도가 미흡한 실정이다. 이에 시각적, 직관적 개념 형성에 적합한 상황과 대상을 제공할 수 있는 컴퓨터 응용소프트웨어를 이용하여 이차곡선을 도입하고 Computer Algebra System을 적용한 MathView를 이용하여 포물선, 타원, 쌍곡선 방정식의 개념 지도 방안을 구안하였다.