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SphereEversion.ToMathlib.Topology.Paracompact

theorem exists_countable_locallyFinite_cover {ι : Type u_1} {X : Type u_2} [TopologicalSpace X] [T2Space X] [LocallyCompactSpace X] [SigmaCompactSpace X] {c : ιX} {W B : ιSet X} {p : ιProp} (hc : Function.Surjective c) (hW₀ : ∀ (i : ι) (r : ), p i rc i W i r) (hW₁ : ∀ (i : ι) (r : ), p i rIsOpen (W i r)) (hB : ∀ (i : ι), (nhds (c i)).HasBasis (p i) (B i)) :
∃ (s : Set (ι × )), s.Countable (∀ zs, (p) z) zs, (W) z = Set.univ LocallyFinite (B Subtype.val)

We could generalise and replace ι × ℝ with a dependent family of types but it doesn't seem worth it. Proof partly based on refinement_of_locallyCompact_sigmaCompact_of_nhds_basis_set.