theorem PiBase.Homeomorph.countablyTightSpace {X : Type u_1} {Y : Type u_2} [TopologicalSpace X] [TopologicalSpace Y] [CountablyTightSpace X] (f : X ≃ₜ Y) : CountablyTightSpace Y

theorem PiBase.WellDefined.countablyTightSpace : WellDefined CountablyTightSpace