∀ {ι : Type t} {X : ι → Type u} [inst : (i : ι) → TopologicalSpace (X i)] {Y : Type v} [tY : TopologicalSpace Y]
  {U : Set (Topology.WithGeneratedByTopology X Y)},
  IsClosed U ↔ ∀ ⦃i : ι⦄ (f : C(X i, Y)), IsClosed (⇑f ⁻¹' (⇑Topology.WithGeneratedByTopology.equiv.symm ⁻¹' U))