• The Pure and Applied Mathematics
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• v.5 no.1
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• pp.45-54
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• 1998

We study the space-times that have a unique terminal indecomposable past set or a unique terminal indecomposable future set and examine their causal boundary, and we investigate some conditions for the warped product space-times of the form (a, b) ${\times}_fF$ to have a unique terminal indecomposable past set or a unique terminal indecomposable future set.

• Communications of the Korean Mathematical Society
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• v.11 no.3
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• pp.783-788
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• 1996

We study some causality characterizations in a space-time by considering chronological common future (or past) sets and indecomposable sets that are important roles in studying causal boundary structure of the space-time.