Goal:
  
  A : Type
  B : Type
  C : Type
  Q : C → Type
  P : C → A → Prop
  fn : ∀ x : A, (∀ y : C, Q y → P y x) → B
  ============================
   (∀ (l : list A) (Hl : ∀ y : C, Q y → ∥ All (P y) l ∥),
      map_All_graph l Hl (map_All l Hl))


DEBUG:Going to execute:
pose proof CoreTactics.the_end_of_the_section as eos