• Bulletin of the Korean Mathematical Society
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• v.55 no.4
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• pp.1125-1135
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• 2018

We show that for an M-action on a compact Hausdorff uniform space, if it has at least two disjoint compact invariant subsets, then it is thickly syndetically sensitive. Additionally, we point out that for a P-M-action of a discrete abelian group on a compact Hausdorff uniform space, the multi-sensitivity is equivalent to both thick sensitivity and thickly syndetic sensitivity.

• 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.

• Honam Mathematical Journal
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• v.41 no.2
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• pp.357-368
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• 2019

We define the concepts of the first and the second module dual of a Banach space X. And also bring a new concept of module amenability for a Banach algebra ${\mathcal{A}}$. For inverse semigroup S, we will give a new action for ${\ell}^1(S)$ as a Banach ${\ell}^1(E_S)$-module and show that if S is amenable then ${\ell}^1(S)$ is ${\ell}^1(E_S)$-module amenable.

• Journal of the Korean Mathematical Society
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• v.52 no.4
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• pp.869-889
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• 2015

Let ${\Gamma}^+$ be the positive cone in a totally ordered abelian group ${\Gamma}$, and ${\alpha}$ an action of ${\Gamma}^+$ by extendible endomorphisms of a $C^*$-algebra A. Suppose I is an extendible ${\alpha}$-invariant ideal of A. We prove that the partial-isometric crossed product $\mathcal{I}:=I{\times}^{piso}_{\alpha}{\Gamma}^+$ embeds naturally as an ideal of $A{\times}^{piso}_{\alpha}{\Gamma}^+$, such that the quotient is the partial-isometric crossed product of the quotient algebra. We claim that this ideal $\mathcal{I}$ together with the kernel of a natural homomorphism $\phi:A{\times}^{piso}_{\alpha}{\Gamma}^+{\rightarrow}A{\times}^{iso}_{\alpha}{\Gamma}^+$ gives a composition series of ideals of $A{\times}^{piso}_{\alpha}{\Gamma}^+$ studied by Lindiarni and Raeburn.

• Journal of applied mathematics & informatics
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• v.6 no.1
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• pp.217-226
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• 1999

In this paper we define automata-linearly independence. An automaton M has a basis B iff M is free provided that we assume that the action of S on X $\times$ S is (x,sa) for all a, s $\in$ S and x $\in$ X. if a semigroup S is PRID every subautomaton of a free S-automaton is free.