isLindelof_iUnion

∀ {X : Type u} [inst : TopologicalSpace X] {ι : Sort u_2} {f : ι → Set X} [Countable ι],
  (∀ (i : ι), IsLindelof (f i)) → IsLindelof (⋃ i, f i)

Defined in: Mathlib.Topology.Compactness.Lindelof
Cited by: 2 results in Mathlib
Foundations: Depth 89 from the axioms · uses propext, Classical.choice, Quot.sound
Assumes: TopologicalSpace Countable

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