• Bulletin of the Korean Mathematical Society
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• v.53 no.1
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• pp.39-48
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• 2016

In this paper we extend Takahashi's fixed point theorem on discrete semigroups to general semi-topological semigroups. Next we define the semi-asymptotic non-expansive action of semi-topological semi-groups to give a partial affirmative answer to an open problem raised by A.T-M. Lau.