no goals
α : Type u_1
β : Type u_2
γ : Type ?u.6214
δ : Type ?u.6217
inst✝³ : TopologicalSpace α
inst✝² : TopologicalSpace β
inst✝¹ : TopologicalSpace γ
inst✝ : TopologicalSpace δ
f : α → β
hf : Inducing f
s : Set α
⊢ IsOpen s ↔ ∃ t, IsOpen t ∧ f ⁻¹' t = s
rw [hf.induced, isOpen_induced_iff]