Description: Every open set belongs to T . This is the second step in the proof of Proposition 121E (f) of Fremlin1 p. 38 . (Contributed by Glauco Siliprandi, 26-Jun-2021)
Ref | Expression | ||
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Hypotheses | smfpimbor1lem1.s | |
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smfpimbor1lem1.f | |
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smfpimbor1lem1.a | |
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smfpimbor1lem1.j | |
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smfpimbor1lem1.8 | |
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smfpimbor1lem1.t | |
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Assertion | smfpimbor1lem1 | |