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perfectlyNormalSpace_iff_forall_isClosed_preimage_zero
Modification history
2026-05-17 12:59
Mathlib/Topology/Separation/PerfectlyNormal.lean
feat(Topology): subspace of a perfectly normal space is perfectly normal (#38533) …
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perfectlyNormalSpace_iff_forall_isClosed_preimage_zero
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