SeparatedNhds.isOpen_left_of_isOpen_union

∀ {X : Type u_1} [inst : TopologicalSpace X] {s t : Set X}, SeparatedNhds s t → IsOpen (s ∪ t) → IsOpen s

Defined in: Mathlib.Topology.Separation.SeparatedNhds
Cited by: 2 results in Mathlib
Foundations: Depth 61 from the axioms · uses propext, Classical.choice, Quot.sound
Assumes: TopologicalSpace

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