• Bulletin of the Korean Mathematical Society
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• v.37 no.4
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• pp.669-674
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• 2000

We define the terminologies for the special type of functions defined on the field $\mathbb{C}$ of complex numbers and consider the solutions of function equations containing such functions in $\mathbb{C}$.

• Journal of the Chungcheong Mathematical Society
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• v.4 no.1
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• pp.91-97
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• 1991

This paper studies the structure and continuity of derivations of the Banach algebra $C^n(I)$ of n times continuously differentiable functions on an interval I into Banach $C^n(I)$-modules.

• Journal of the Chungcheong Mathematical Society
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• v.15 no.2
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• pp.13-23
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• 2003

We prove a simplicity of the $C^*$-algebra generated by some $C^*$-subalgebra and a Haar unitary in a free product of finite von Neumann algebras. Some examples and questions are given.

• Communications of the Korean Mathematical Society
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• v.12 no.1
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• pp.75-78
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• 1997

We show that if a simple $C^*$-algebra A satisfies certain $K_1$-group conditions, then two unitarily equivalent projections are homotopic. Also we show that the equivalence of projections determined by a dimension function is a homotopy.

• East Asian mathematical journal
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• v.5 no.2
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• pp.177-189
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• 1989

• Communications of the Korean Mathematical Society
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• v.8 no.2
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• pp.267-274
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• 1993

• Journal of the Korean Mathematical Society
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• v.36 no.1
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• pp.97-107
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• 1999

Given a C-dynamical system (A, G, $\alpha$) with a locally compact group G, two kinds of C-algebras are made from it, called the full C-crossed product and the reduced C-crossed product. In this paper, we extend the theory of the classical C-crossed product to the C-dynamical system (A, G, $\alpha$) with a left-cancellative semigroup M with unit. We construct a new C-algebra A $\alpha$rM, the reduced crossed product of A by the semigroup M under the action $\alpha$ and investigate some properties of A $\alpha$rM.

• The Pure and Applied Mathematics
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• v.12 no.1
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• pp.1-15
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• 2005

We study continuous fields and K-groups of crossed products of C＊-algebras. It is shown under a reasonable assumption that there exist continuous fields of C＊ -algebras between crossed products of C＊ -algebras by amenable locally compact groups and tensor products of C＊ -algebras with their group C＊ -algebras, and their K-groups are the same under the additional assumptions.

• Journal of the Korean School Mathematics Society
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• v.13 no.2
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• pp.243-262
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• 2010

CRESST(the National Center for Research on Evaluation, Standards, and Student Testing at UCLA) is now carrying out the research, which was scheduled for a five year period from 2007 to 2011. This research aimed at testing the effectiveness of the formative assessment program by continuously conducting the program on the target group and steadily applying the recurring feedback, in order to reform the teachers' teaching and to facilitate students' learning. To do this, CRESST has set out to develop the material for 7th graders since January 2007, and KICE(Korea Institute of Curriculum and Evaluation) have been running a collaborated research since July 2007, while sharing the instructional materials developed by CRESST. In 2008, the pre-test was conducted prior to this study in 2009. Especially, this paper deals with the Korean 7th graders' scholastic achievements in algebra domain measured by PowerSource(c). In addition, this study would examine the responses of teachers and students on its application.

• Bulletin of the Korean Mathematical Society
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• v.37 no.2
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• pp.249-254
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• 2000

We give an easy proof of the fact that every noncommutative torus $A_{\omega}$ is stably isomorphic to the noncommutative torus $C(\widehat{S\omega}){\;}\bigotimes{\;}A_p$ which hasa trivial bundle structure. It is well known that stable isomorphism of two separable $C^{*}-algebras$ is equibalent to the existence of eqivalence bimodule between the two stably isomorphic $C^{*}-algebras{\;}A_{\omega}$ and $C(\widehat{S\omega}){\;}\bigotimes{\;}A_p$.