Description: The intersection of interiors of a every pair is a subset of the interior of the intersection of the pair if an only if the closure of the union of every pair is a subset of the union of closures of the pair. (Contributed by RP, 19-Jun-2021)
Ref | Expression | ||
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Hypotheses | ntrcls.o | |
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ntrcls.d | |
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ntrcls.r | |
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Assertion | ntrclsk3 | |