no goals
ι : Type ?u.4968
B : Type u_2
F : Type u_3
E : B → Type ?u.4979
Z : Type u_1
inst✝¹ : TopologicalSpace B
inst✝ : TopologicalSpace F
proj : Z → B
e : Pretrivialization F proj
x : Z
⊢ x ∈ e.source ↔ proj x ∈ e.baseSet
rw [e.source_eq, mem_preimage]