• 대한수학교육학회지:학교수학
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• 제9권3호
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• pp.409-426
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• 2007

중등학교의 핵심교과로 긴 세월 동안 기호와 식의 조작이 중심이 되어 왔던 대수교육은 보편교육의 확대와 컴퓨터나 계산기 등 ICT의 편재로 그 적절성을 재고하게 하였다. 이 연구는 대수교육과정 개혁의 방향을 살펴보고, 국내 대수교육과정 연구와 실행에 시사점을 제시하기 계획되었다. 최근 대수교육의 개혁의 큰 흐름의 특징으로 대수교육을 사고교육으로 보아 대수적 사고나 추론 강조, 비형식적 대수 교육에 주목한 대수 대상 연령의 하향화, ICT 환경을 전제로 한 대수교육으로 정리하였다. ICT 환경에서의 특징적인 대수 활동을 제시하였다. ICT 활용과 관련하여 구체적인 사례를 통해 국내 중등대수 교육과정을 분석하고 본질적으로 대수교육이 전통적인 틀 안에 있게 된 이유와 국제 동향을 반영한 변화를 위한 과제를 제시하였다.

• 대한수학회보
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• 제33권3호
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• pp.359-366
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• 1996

A linear map T from a Banach algebra A into a Banach algebra B is almost multiplicative if $\left\$\mid$ T(fg) - T(f)T(g) \right\$\mid$ \leq \in\left\$\mid$ f \right\$\mid$\left\$\mid$ g \right\$\mid$(f,g \in A)$ for some small positive $\in$. B.E.Johnson [4,5] studied whether this implies that T is near a multiplicative map in the norm of operators from A into B. K. Jarosz [2,3] raised the conjecture : If T is an almost multiplicative functional on uniform algebra A, there is a linear and multiplicative functional F on A such that $\left\$\mid$ T - F \right\$\mid$ \leq \in', where \in' \to 0$ as $\in \to 0$. B. E. Johnson [4] gave an example of non-uniform commutative Banach algebra which does not have the property described in the above conjecture. He proved also that C(K) algebras and the disc algebra A(D) have this property [5]. We extend this property to a derivation on a Banach algebra.

• 대한수학회보
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• 제46권5호
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• pp.1031-1040
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• 2009

It is shown that every almost positive linear mapping h : $\mathcal{A}\rightarrow\mathcal{B}$ of a Banach *-algebra $\mathcal{A}$ to a Banach *-algebra $\mathcal{B}$ is a positive linear operator when h(rx) = rh(x) (r > 1) holds for all $x\in\mathcal{A}$, and that every almost linear mapping h : $\mathcal{A}\rightarrow\mathcal{B}$ of a unital C*-algebra $\mathcal{A}$ to a unital C*-algebra $\mathcal{B}$ is a positive linear operator when h($2^nu*y$) = h($2^nu$)*h(y) holds for all unitaries $u\in \mathcal{A}$, all $y \in \mathcal{A}$, and all n = 0, 1, 2, ..., by using the Hyers-Ulam-Rassias stability of functional equations. Under a more weak condition than the condition as given above, we prove that every almost linear mapping h : $\mathcal{A}\rightarrow\mathcal{B}$ of a unital C*-algebra $\mathcal{A}$ A to a unital C*-algebra $\mathcal{B}$ is a positive linear operator. It is applied to investigate states, center states and center-valued traces.

• 대한수학교육학회지:학교수학
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• 제2권1호
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• pp.29-51
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• 2000

In this study, we tried to suggest an example of the analysis on the use of mathematical manipulatives. Taking algebra tiles as an example of mathematical manipulatives, we analysed several effects resulted from the use of algebra tiles. The algebra tiles make it possible to do activities that are needed to introduce and explain the distributive law and factoring. The algebra tiles have a several advantages; First of all, This model is simple. Even though they cannot make algebra easy, this model can play an important role in the transition to a new algebra course. This model provides access to symbol manipulation for students who had previously been frozen out of the course because of their weak number sense. This model provides a geometric interpretation of symbol manipulation, thereby enriching students' understanding, This model supports cooperative learning, and help improve discourse in the algebra class by giving students objects to think with and talk about. On the other hand, The disadvantages of this model are as follows; the model reinforces the misconception that -x is negative, and x is positive; the area model of multiplication is not geometrically sound when minus is involved; only the simplest expressions involving minus can be represented; It is ineffective when be used the learning of already known concept. Mathematics teachers must have a correct understanding about these advantages and disadvantages of manipulatives. Therefore, they have to plan classroom work that be maximized the positive effect of manipulatives and minimized the negative effect of manipulatives.

• 대한수학회지
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• 제56권5호
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• pp.1333-1354
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• 2019

In authors' paper in 2007, it was shown that the BSE-extension of $C^1_0(R)$, the algebra of continuously differentiable functions f on the real number space R such that f and df /dx vanish at infinity, is the Lipschitz algebra $Lip_1(R)$. This paper extends this result to the case of $C^n_0(R^d)$ and $C^{n-1,1}_b(R^d)$, where n and d represent arbitrary natural numbers. Here $C^n_0(R^d)$ is the space of all n-times continuously differentiable functions f on $R^d$ whose k-times derivatives are vanishing at infinity for k = 0, ${\cdots}$, n, and $C^{n-1,1}_b(R^d)$ is the space of all (n - 1)-times continuously differentiable functions on $R^d$ whose k-times derivatives are bounded for k = 0, ${\cdots}$, n - 1, and (n - 1)-times derivatives are Lipschitz. As a byproduct of our investigation we obtain an important result that $C^{n-1,1}_b(R^d)$ has a predual.

• 대한수학회보
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• 제42권3호
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• pp.453-467
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• 2005

Let K be an algebraic number field. If k is the maximal cyclotomic subextension in K then the Schur K-group S(K) is obtained from the Schur k-group S(k) by scalar extension. In the paper we study projective Schur group PS(K) which is a generalization of Schur group, and prove that a projective Schur K-algebra is obtained by scalar extension of a projective Schur k-algebra where k is the maximal radical extension in K with mild condition.

• 호남수학학술지
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• 제27권4호
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• pp.583-593
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• 2005

The Weyl-type non-associative algebra ${\overline{WN_{g_n,m,s_r}}$ and its subalgebra ${\overline{WN_{n,m,s_r}}$ are defined and studied in the papers [2], [3], [9], [11], [12]. We find the derivation group $Der_{non}({\overline{WN_{1,0,0_{[2]}}})$ the non-associative simple algebra ${\overline{WN_{1,0,0_{[2]}}}$.

• 충청수학회지
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• 제26권4호
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• pp.703-706
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• 2013

Let R be a commutative noetherian algebra and let ${\delta}$ be a nonzero derivation. Here we determine the prime ideals of the skew polynomial algebra R[z;${\delta}$] and the Poisson prime ideals of R[z;${\delta}$]p.

• 호남수학학술지
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• 제19권1호
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• pp.21-27
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• 1997

We shall define three kinds of points for algebraic varieties associated to the center 3 of U(L) which is the universal enveloping algebra of a finite-dimensional modular Lie algebra over an algebraically closed field F of prime characteristic p. We announce here that $sp_4$(F) with p = 2 has a subregular point.

• 호남수학학술지
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• 제28권1호
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• pp.113-124
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• 2006

In this article, we show that for an approximate derivation on a Banach *-algebra, there exist a unique derivation near the an approximate derivation and for an approximate derivation on a $C^*$-algebra, there exist a unique derivation near the approximate derivation.