• Journal of applied mathematics & informatics
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• v.34 no.1_2
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• pp.1-7
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• 2016

Some properties of filters are studied with respect to a congru-ence of BE-algebras. The notion of θ-filters is introduced and these classes of filters are then characterized in terms of congruence classes. A bijection is obtained between the set of all θ-filters of a BE-algebra and the set of all filters of the respective BE-algebra of congruences classes.

• Bulletin of the Korean Mathematical Society
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• v.53 no.1
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• pp.153-161
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• 2016

It is shown that the algebra $\mathfrak{H}^{\infty}$ of bounded Dirichlet series is not a coherent ring, and has infinite Bass stable rank. As corollaries of the latter result, it is derived that $\mathfrak{H}^{\infty}$ has infinite topological stable rank and infinite Krull dimension.

• Bulletin of the Korean Mathematical Society
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• v.44 no.1
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• pp.95-102
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• 2007

We define the non-associative algebra $\bar{W(n,m,m+s)}$) and we show that it is simple. We find the non-associative algebra automorphism group $Aut_{non}\bar{(W(1,0,0))}\;of\;\bar{W(1,0,0)}$. Also we find that any derivation of $\bar{W(1,0,0)}$ is a scalar derivation in this paper.

• Korean Journal of Mathematics
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• v.15 no.2
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• pp.135-148
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• 2007

We prove the stability of generalized Jensen's equations in a Hilbert module over a unital $C^*$-algebra. This is applied to show the stability of a projection, a unitary operator, a self-adjoint operator, a normal operator, and an invertible operator in a Hilbert module over a unital $C^*$-algebra.

• Journal of applied mathematics & informatics
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• v.9 no.2
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• pp.845-850
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• 2002

Given vectors x and y in a filbert space H, an interpolating operator for vectors is a bounded operator T such that Tx = y. An interpolating operator for n vectors satisfies the equation $Tx_i=y_i$, for i = 1, 2 …, n. In this article, we investigate self-adjoint interpolation problems for vectors in tridiagonal algebra.

• Korean Journal of Mathematics
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• v.25 no.2
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• pp.163-179
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• 2017

In this paper, we introduce the notion of left derivations of BCH algebras and investigate some properties of left derivations in a BCH-algebra. Moreover, we introduce the notions of fixed set and kernel set of derivations in a BCH-algebra and obtained some interesting properties in medial BCH-algebras. Also, we discuss the relations between ideals in a medial BCH-algebras.

• Bulletin of the Korean Mathematical Society
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• v.34 no.2
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• pp.193-198
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• 1997

In order to research the logical system whose propositional value is given in a lattice, Y. Xu [4] proposed the concept of lattice implication algebras, and discussed their some properties in [3] and [4]. Y. Xu and K. Qin [5] introduced the notions of filter and implicative filter in a lattice implication algebra, and investigated their properties. In this paper, in the first place, we give an equivalent condition of a filter, and provide some equivalent conditions that a filter is an implicative filter in a lattice implication algebra. By using these results, we construct an extension property for implicative filter.

• Bulletin of the Korean Mathematical Society
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• v.52 no.3
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• pp.717-734
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• 2015

In this paper, we provide a classification of arithmetic functions in terms of identically-free-distributedness, determined by a fixed prime. We show then such classifications are free from the choice of primes. In particular, we obtain that the algebra $A_p$ of equivalence classes under the quotient on A by the identically-free-distributedness is isomorphic to an algebra $\mathbb{C}^2$, having its multiplication $({\bullet});(t_1,t_2){\bullet}(s_1,s_2)=(t_1s_1,t_1s_2+t_2s_1)$.

• Communications of the Korean Mathematical Society
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• v.22 no.1
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• pp.1-7
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• 2007

Subtraction algebras with additional conditions, so called complicated subtraction algebras, are introduced, and several properties are investigated. In a complicated subtraction algebra, characterizations of ideals are provided, and showed that the set of all ideals in a complicated subtraction algebra is a complete lattice.

• Korean Journal of Mathematics
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• v.7 no.1
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• pp.71-77
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• 1999

We show that if the stable rank of $B^{\alpha}$ is one, then the stable rank of B is less than or equal to the order of G for any action of a finite group G. Also we give a short proof to the known fact that if the action of a finite group on a $C^*$-algebra B is saturated then the canonical conditional expectation from B to $B^{\alpha}$ is of index-finite type and the crossed product $C^*$-algebra is isomorphic to the algebra of compact operators on the Hilbert $B^{\alpha}$-module B.