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Theorems · Theorem · general topology

Filter.exists_antitone_basis

∀ {α : Type u_1} (f : Filter α) [f.IsCountablyGenerated], ∃ x, f.HasAntitoneBasis x

A countably generated filter admits a basis formed by an antitone sequence of sets.

Defined in
Mathlib.Order.Filter.CountablyGenerated
Cited by
10 results in Mathlib
Foundations
Depth 64 from the axioms · uses propext, Classical.choice, Quot.sound
Assumes
Filter.IsCountablyGenerated

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Cited by10

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