• Journal of applied mathematics & informatics
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• v.14 no.1_2
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• pp.423-427
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• 2004

For any completely regular Hausdorff space weighted operator on $C_{b}(X)$ is not necessarily compact. In this paper we find both necessary and sufficient conditions for a weighted operator on $C_{b}(X)$ to be compact. And known results in $uC_{\Phi}$ are shown to emerge as special cases.

• The Pure and Applied Mathematics
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• v.13 no.3 s.33
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• pp.227-236
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• 2006

The purpose of this paper is to establish a random fixed point theorem for nonconvex valued random multivalued operators, which generalize known results in the literature. We also derive a random coincidence fixed point theorem in the noncompart setting.

• Communications of the Korean Mathematical Society
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• v.29 no.3
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• pp.401-408
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• 2014

If A is a unital Banach algebra, then the spectrum can be viewed as a function ${\sigma}$ : 𝕬 ${\rightarrow}$ 𝕾, mapping each T ${\in}$ 𝕬 to its spectrum ${\sigma}(T)$, where 𝕾 is the set, equipped with the Hausdorff metric, of all compact subsets of $\mathbb{C}$. This paper is concerned with the continuity of the spectrum ${\sigma}$ via Browder's theorem. It is shown that ${\sigma}$ is continuous when ${\sigma}$ is restricted to the set of essentially hyponormal operators for which Browder's theorem holds, that is, the Weyl spectrum and the Browder spectrum coincide.