• Korean Journal of Mathematics
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• 제2권
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• pp.7-12
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• 1994

• 대한수학회논문집
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• 제21권4호
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• pp.787-794
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• 2006

Two main results are presented in relation to subordination, self-decomposability and semi-stability. One of the result is that strict semi-stability of subordinand process by selfdecomposable subordinator gives semi-selfdecomposability of the subordinated process. The second result is a sufficient condition for any subordinated process arising from a semi-stable subordinand and a semi-stable subordinator to be semi-selfdecomposable.

• 대한수학회지
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• 제50권2호
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• pp.361-377
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• 2013

In this work we deal with the problem of how to squeeze multiple ciphertexts without losing original message information. To do so, we formalize the notion of decomposability for public-key encryption and investigate why adding decomposability is challenging. We construct an ElGamal encryption scheme over extension fields, and show that it supports the efficient decomposition. We then analyze security of our scheme under the standard DDH assumption, and evaluate the performance of our construction.

• 대한수학회보
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• 제48권1호
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• pp.183-195
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• 2011

In this paper we show that Helton class preserves the nilpotent and finite ascent properties. Also, we show some relations on non-transitivity and decomposability between operators and their Helton classes. Finally, we give some applications in the Helton class of weighted shifts.

• 충청수학회지
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• 제28권3호
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• pp.419-429
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• 2015

In this paper, we study properties SVEP, Bishop's property (${\beta}$), property (${\delta}$), decomposability, property $({\beta})_{\epsilon}$, subscalarity, Kato spectrum, generalized Kato decomposition, finite ascent for bounded linear operators in Banach spaces.

• 말소리와 음성과학
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• 제14권3호
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• pp.67-76
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• 2022

This paper presents two experiments examining different gemination behavior of English affixes. Experiment 1 focused on geminates through affixation with im-, un-, -ness, and -ly. The English group articulated geminates with longer absolute and relative durations than singletons for im-, un-, and -ness, but there was no difference for -ly. This suggests that -ly words are more likely to be perceived as whole words, and that -ly is less decomposable. Furthermore, un- geminates exhibited longer absolute and preceding vowel durations than im- geminates, suggesting that im- is more decomposable than un-. However, the Korean group produced geminates with longer absolute and relative durations than singletons for all im-, un-, -ness, and -ly, and produced comparable absolute durations of im- and un- geminates. Experiment 2 investigated different gemination behaviors of locative and negative im- prefixes. The English group showed durational contrast between geminates and singletons only for negative im-, indicating that locative im- is not easily separated from stem. However, the Korean group produced longer absolute and relative durations for geminates than for singletons for both locative and negative im-. According to the findings of Experiments 1 and 2, affix decomposability is less likely to influence Korean speakers' English affix gemination, and spellings may have a greater influence.

• Journal of applied mathematics & informatics
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• 제40권3_4호
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• pp.785-794
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• 2022

In this paper we show that if A ∈ L(X) and R ∈ L(X) is a quasinilpotent operator commuting with A then X_A(F) = X_A+R(F) for all subset F ⊆ ℂ and 𝜎_loc(A) = 𝜎_loc(A + R). Moreover, we show that A and A + R share many common local spectral properties such as SVEP, property (C), property (𝛿), property (𝛽) and decomposability. Finally, we show that quasisimility preserves local spectrum.

• 충청수학회지
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• 제29권4호
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• pp.543-552
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• 2016

In this paper we investigate the local spectral properties of quasidecomposable operators. We show that if $T{\in}L(X)$ is quasi-decomposable, then T has the weak-SDP and ${\sigma}_{loc}(T)={\sigma}(T)$. Also, we show that the quasi-decomposability is preserved under commuting quasi-nilpotent perturbations. Moreover, we show that if $f:U{\rightarrow}{\mathbb{C}}$ is an analytic and injective on an open neighborhood U of ${\sigma}(T)$, then $T{\in}L(X)$ is quasi-decomposable if and only if f(T) is quasi-decomposable. Finally, if $T{\in}L(X)$ and $S{\in}L(Y)$ are asymptotically similar, then T is quasi-decomposable if and only if S does.

• 대한수학회지
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• 제41권3호
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• pp.479-487
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• 2004

Let G be a finite group and N be a normal subgroup of G. We denote by ncc(N) the number of conjugacy classes of N in G and N is called n-decomposable, if ncc(N) = n. Set $K_{G}\;=\;\{ncc(N)$\mid$N{\lhd}G\}$. Let X be a non-empty subset of positive integers. A group G is called X-decomposable, if KG = X. In this paper we characterise the {1, 3, 4}-decomposable finite non-perfect groups. We prove that such a group is isomorphic to Small Group (36, 9), the $9^{th}$ group of order 36 in the small group library of GAP, a metabelian group of order $2^n{2{\frac{n-1}{2}}\;-\;1)$, in which n is odd positive integer and $2{\frac{n-1}{2}}\;-\;1$ is a Mersenne prime or a metabelian group of order $2^n(2{\frac{n}{3}}\;-\;1)$, where 3$\mid$n and $2\frac{n}{3}\;-\;1$ is a Mersenne prime. Moreover, we calculate the set $K_{G}$, for some finite group G.

• 대한수학회지
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• 제55권2호
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• pp.391-413
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• 2018

In this paper we introduce a new tensor named semi-projective curvature tensor which generalizes the projective curvature tensor. First we deduce some basic geometric properties of semi-projective curvature tensor. Then we study pseudo semi-projective symmetric manifolds $(PSPS)_n$ which recover some known results of Chaki [5]. We provide several interesting results. Among others we prove that in a $(PSPS)_n$ if the associated vector field ${\rho}$ is a unit parallel vector field, then either the manifold reduces to a pseudosymmetric manifold or pseudo projective symmetric manifold. Moreover we deal with semi-projectively flat perfect fluid and dust fluid spacetimes respectively. As a consequence we obtain some important theorems. Next we consider the decomposability of $(PSPS)_n$. Finally, we construct a non-trivial Lorentzian metric of $(PSPS)_4$.