∀ {B : Type u_1} {F : Type u_2} {Z : Type u_3} [inst : TopologicalSpace B] [inst_1 : TopologicalSpace F] {s : Set B},
  IsOpen s → ∀ {proj : Z → ↑s} (e : Bundle.Pretrivialization F proj), IsOpen (Subtype.val '' e.baseSet)