∀ {F : Type u_3} {M : Type u_1} {N : Type u_2} [inst : Preorder M] [inst_1 : Preorder N] [inst_2 : EquivLike F M N]
  [OrderIsoClass F M N] (f : F) [inst_4 : LocallyFiniteOrder N] (a b x : M),
  x ∈ Finset.map { toFun := EquivLike.inv f, inj' := ⋯ } (LocallyFiniteOrder.finsetIcc (f a) (f b)) ↔ a ≤ x ∧ x ≤ b