• 대한수학회보
• /
• 제43권1호
• /
• pp.189-212
• /
• 2006

Let $F^{\alpha}G$ be a twisted group algebra with basis ${{\mu}g|g\;{\in}\;G}$ and $P\;=\;{C_g|g\;{\in}\;G}$ be a partition of G. A projective class algebra associated with P is a subalgebra of $F^{\alpha}G$ generated by all class sums $\sum\limits{_{x{\in}C_g}}\;{\mu}_x$. A main object of the paper is to find interrelationships of projective class algebras in $F^{\alpha}G$ and in $F^{\alpha}H$ for H < G. And the a-spherical function will play an important role for the purpose. We find functional properties of a-spherical functions and investigate roles of $\alpha-spherical$ functions as characters of projective class algebras.

• 대한수학회지
• /
• 제42권5호
• /
• pp.1031-1056
• /
• 2005

In this paper, we define the conditional first variation over Wiener paths in abstract Wiener space and investigate its properties. Using these properties, we also investigate relationships among first variation, conditional first variation, Fourier-Feynman transform and conditional Fourier-Feynman transforms of functions in a Banach algebra which is equivalent to the Fresnel class. Finally, we provide another method evaluating the Fourier-Feynman transform for the product of a function in the Banach algebra with n linear factors.

• Kyungpook Mathematical Journal
• /
• 제52권2호
• /
• pp.189-200
• /
• 2012

In this article we introduce the class of I-convergent double sequences of fuzzy real numbers. We have studied different properties like solidness, symmetricity, monotone, sequence algebra etc. We prove that the class of I-convergent double sequences of fuzzy real numbers is a complete metric spaces.

• 대한수학회보
• /
• 제20권2호
• /
• pp.71-74
• /
• 1983

The problems of the continuity of homomorphisms between Banach algebras have been studied widely for the last two decades to obtain various fruitful results, yet it is far from characterizing the calss of Banach algebras for which each homomorphism from a member of the class into a Banach algebra is conitnuous. For commutative Banach algebras A and B a simple proof shows that every homomorphism .theta. from A into B is continuous provided that B is semi-simple, however, with a non semi-simple Banach algebra B examples of discontinuous homomorphisms from C(K) into B have been constructed by Dales [6] and Esterle [7]. For non commutative Banach algebras the problems of automatic continuity of homomorphisms seem to be much more difficult. Many positive results and open questions related to this subject may be found in [1], [3], [5] and [8], in particular most recent development can be found in the Lecture Note which contains [1]. It is well-known that a$^{*}$-isomorphism from a $C^{*}$-algebra into another $C^{*}$-algebra is an isometry, and an isomorphism of a Banach algebra into a $C^{*}$-algebra with self-adjoint range is continuous. But a$^{*}$-isomorphism from a $C^{*}$-algebra into an involutive Banach algebra is norm increasing [9], and one can not expect each of such isomorphisms to be continuous. In this note we discuss an isomorphism from a commutative $C^{*}$-algebra into a commutative Banach algebra with dense range via separating space. It is shown that such an isomorphism .theta. : A.rarw.B is conitnuous and maps A onto B is B is semi-simple, discontinuous if B is not semi-simple.

• 호남수학학술지
• /
• 제44권2호
• /
• pp.165-178
• /
• 2022

In this paper, Sheffer stroke BL-algebra and its properties are investigated. It is shown that a Cartesian product of two Sheffer stroke BL-algebras is a Sheffer stroke BL-algebra. After describing a filter of Sheffer stroke BL-algebra, a congruence relation on a Sheffer stroke BL-algebra is defined via its filter, and quotient of a Sheffer stroke BL-algebra is constructed via a congruence relation. Also, it is defined a homomorphism between Sheffer stroke BL-algebras and is presented its properties. Thus, it is stated that the class of Sheffer stroke BL-algebras forms a variety.

• 한국수학교육학회지시리즈E:수학교육논문집
• /
• 제30권1호
• /
• pp.1-22
• /
• 2016

본 연구에서는 문헌 및 사례 분석을 통해 효과적인 플립드러닝 강의 모델을 모색해 보고, 그간 대학에서의 '선형대수학' 강좌를 위하여 시도한 다양한 플립드러닝 강의 경험을 정리하여 '선형대수학' 강의 모델을 개발하고 실제 강의 현장에 적용해 플립드러닝의 효과를 연구자의 입장에서 뿐만 아니라 학습자의 관점에서도 그 과정과 결과를 분석하며 검증하였다. 그 결과, 플립드러닝은 학생들이 미리 온라인 동영상 강의를 듣고 수업에 참여하므로 다양한 학습자 중심의 활동으로 구성이 가능하며, 따라서 수학적 지식 습득에 성취감을 고취시킬 뿐 아니라 학생들의 참여도와 자신감 그리고 도전의욕 증가에 유의미한 영향을 준 것을 충분한 데이터와 설문조사를 최신 통계기법을 활용하여 분석함으로 확인하였다.

• 대한수학회보
• /
• 제54권4호
• /
• pp.1443-1455
• /
• 2017

Let $M_{z^N}(N{\in}{\mathbb{Z}}^d_+)$ be a bounded multiplication operator on a class of Hilbert spaces with orthogonal basis $\{z^n:n{\in}{\mathbb{Z}}^d_+\}$. In this paper, we prove that each reducing subspace of $M_{z^N}$ is the direct sum of some minimal reducing subspaces. For the case that d = 2, we find all the minimal reducing subspaces of $M_{z^N}$ ($N=(N_1,N_2)$, $N_1{\neq}N_2$) on weighted Bergman space $A^2_{\alpha}({\mathbb{B}}_2)$(${\alpha}$ > -1) and Hardy space $H^2({\mathbb{B}}_2)$, and characterize the structure of ${\mathcal{V}}^{\ast}(z^N)$, the commutant algebra of the von Neumann algebra generated by $M_{z^N}$.

• Kyungpook Mathematical Journal
• /
• 제49권1호
• /
• pp.1-6
• /
• 2009

Let B(X) denote the algebra of operators on a complex Banach space X, H(X) = {h ${\in}$ B(X) : h is hermitian}, and J(X) = {x ${\in}$ B(X) : x = $x_1$ + $ix_2$, $x_1$ and $x_2$ ${\in}$ H(X)}. Let ${\delta}_a$ ${\in}$ B(B(X)) denote the derivation ${\delta}_a$ = ax - xa. If J(X) is an algebra and ${\delta}_a^{-1}(0){\subseteq}{\delta}_{a^*}^{-1}(0)$ for some $a{\in}J(X)$, then ${\parallel}a{\parallel}{\leq}{\parallel}a-(x^*x-xx^*){\parallel}$ for all $x{\in}J(X){\cap}{\delta}_a^{-1}(0)$. The cases J(X) = B(H), the algebra of operators on a complex Hilbert space, and J(X) = $C_p$, the von Neumann-Schatten p-class, are considered.

• 한국통신학회논문지
• /
• 제30권1C호
• /
• pp.1-8
• /
• 2005

본 논문에서는 이중 대각 부행렬에 근거한 결정적 LDPC 부호의 일종인 반집합 대수 LDPC 행렬이라는 새로운 LDPC 부호의 구성을 제시한다. 이러한 구성 방법에 의해 일종의 high rate LDPC 부호를 얻게 되며, 이 부류의 부호들은 큰 girth와 양호한 최소거리 특성을 갖는다. 또한, 순환 시프트 레지스터를 이용한 단순한 병렬 어레이 구조로 구현할 수 있으며, 반복 복호에 의해 용이하게 처리될 수 있다.

• 대한수학회지
• /
• 제32권3호
• /
• pp.635-647
• /
• 1995

Let $H$ denote a separable, infinite dimensional complex Hilbert space and let $L(H)$ denote the algebra of all bounded linear operators on $H$. A dual algebra is a subalgebra of $L(H)$ that contains the identity operator $1_H$ and is closed in the $weak^*$ operator topology on $L(H)$. For $T \in L(H)$, let $A_T$ denote the smallest subalgebra of $L(H)$ that contains T and $1_H$ and is closed in the $weak^*$ operator topology.