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  • P-ISSN3059-0604
  • E-ISSN3059-1309
  • KCI

Vol.11 No.2

Helmuth Spath pp.105-115
Chang, Gyu-Whan pp.117-125
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Abstract

Let T be an integral domain, M a nonzero maximal ideal of T, K = T/M, <TEX>$\psi$</TEX>: T \longrightarrow K the canonical map, D a proper subring of K, and R = <TEX>$\psi^{-1}$</TEX>(D) the pullback domain. Assume that for each <TEX>$x \; \in T$</TEX>, there is a <TEX>$u \; \in T$</TEX> such that u is a unit in T and <TEX>$ux \; \in R$</TEX>, . In this paper, we show that R is a weakly Krull domain (resp., GWFD, AWFD, WFD) if and only if htM = 1, D is a field, and T is a weakly Krull domain (resp., GWFD, AWFD, WFD).

Davvaz, B. pp.127-132
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Abstract

<TEX>$H_v$</TEX>-rings first were introduced by Vougiouklis in 1990. The largest class of algebraic systems satisfying ring-like axioms is the <TEX>$H_v$</TEX>-ring. Let R be an <TEX>$H_v$</TEX>-ring and <TEX>${\gamma}_R$</TEX> the smallest equivalence relation on R such that the quotient <TEX>$R/{\gamma}_R$</TEX>, the set of all equivalence classes, is a ring. In this case <TEX>$R/{\gamma}_R$</TEX> is called the fundamental ring. In this short communication, we study the fundamental rings with respect to the product of two fuzzy subsets.

Lee, Dong-Myung ; Lee, Jeong-Gon ; Cui, Ming-Gen pp.133-138
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Abstract

In this paper we derive a decomposition of the solution of Fredholm equations of the second kind in terms of reproducing kernels in the space <TEX>${W_2}^2$</TEX>(<TEX>$\Omega$</TEX>)

Kim, Tae-Sung ; Ko, Mi-Hwa ; Ro, Hyeong-Hee pp.139-147
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Abstract

Let {<<TEX>$\mathds{X}_t$</TEX>} be an m-dimensional linear process of the form <TEX>$\mathbb{X}_t\;=\sumA,\mathbb{Z}_{t-j}$</TEX> where {<TEX>$\mathbb{Z}_t$</TEX>} is a sequence of stationary m-dimensional negatively associated random vectors with <TEX>$\mathbb{EZ}_t$</TEX> = <TEX>$\mathbb{O}$</TEX> and <TEX>$\mathbb{E}\parallel\mathbb{Z}_t\parallel^2$</TEX> < <TEX>$\infty$</TEX>. In this paper we prove the central limit theorems for multivariate linear processes generated by negatively associated random vectors.

Hwang, Sun-Wook ; Kwon, Oh-Sang pp.149-154
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Abstract

We show that the Choquet boundary of the tensor product of two real function algebras is the product of their Choquet boundaries.

Lee, Byung-Soo ; Kang, Mee-Kwang pp.155-166
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Abstract

In this paper, we introduce new monotone concepts for set-valued mappings, called generalized C(x)-L-pseudomonotonicity and weakly C(x)-L-pseudomonotonicity. And we obtain generalized Minty-type lemma and the existence of solutions to vector variational inequality problems for weakly C(x)-L-pseudomonotone set-valued mappings, which generalizes and extends some results of Konnov & Yao [11], Yu & Yao [20], and others Chen & Yang [6], Lai & Yao [12], Lee, Kim, Lee & Cho [16] and Lin, Yang & Yao [18].

Jo, Young-Soo ; Kang, Joo-Ho pp.167-173
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Abstract

Given vectors x and y in a separable Hilbert space <TEX>$\cal H$</TEX>, an interpolating operator is a bounded operator A such that Ax = y. In this article, we investigate Hilbert-Schmidt interpolation problems for vectors in a tridiagonal algebra. We show the following: Let <TEX>$\cal L$</TEX> be a subspace lattice acting on a separable complex Hilbert space <TEX>$\cal H$</TEX> and let x = (<TEX>$x_{i}$</TEX>) and y = (<TEX>$y_{i}$</TEX>) be vectors in <TEX>$\cal H$</TEX>. Then the following are equivalent; (1) There exists a Hilbert-Schmidt operator A = (<TEX>$a_{ij}$</TEX> in Alg<TEX>$\cal L$</TEX> such that Ax = y. (2) There is a bounded sequence {<TEX>$a_n$</TEX> in C such that <TEX>${\sum^{\infty}}_{n=1}\mid\alpha_n\mid^2 < \infty$</TEX> and <TEX>$y_1 = \alpha_1x_1 + \alpha_2x_2$</TEX> ... <TEX>$y_{2k} =\alpha_{4k-1}x_{2k}$</TEX> <TEX>$y_{2k=1} = \alpha_{4kx2k} + \alpha_{4k+1}x_{2k+1} + \alpha_{4k+1}x_{2k+2}$</TEX> for K <TEX>$\epsilon$</TEX> N.

Journal of the Korean Society of Mathematical Education Series B: Theoretical Mathematics and Pedagogical Mathematics