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

theorem PiBase.WellDefined.hasFinitelyManyOpenSets : WellDefined HasFinitelyManyOpenSets