diff --git a/Analysis/MeasureTheory/Section_1_2_1.lean b/Analysis/MeasureTheory/Section_1_2_1.lean
index 2ed00d71..3c9e524f 100644
--- a/Analysis/MeasureTheory/Section_1_2_1.lean
+++ b/Analysis/MeasureTheory/Section_1_2_1.lean
@@ -4340,7 +4340,8 @@ theorem Box.sum_volume_eq {d:ℕ} (B B': ℕ → Box d) (hdisj: Pairwise (Functi
 /-- Exercise 1.2.5: For any set that equals a countable union of almost disjoint boxes,
     the Lebesgue outer measure equals the Jordan inner measure. -/
 theorem Lebesgue_outer_measure.eq_Jordan_inner_of_boxes {d:ℕ} (E: Set (EuclideanSpace' d)) (B: ℕ → Box d)
-    (hE: E = ⋃ n, (B n).toSet) (hdisj: Pairwise (Function.onFun AlmostDisjoint B)) :
+    (hE: E = ⋃ n, (B n).toSet) (hdisj: Pairwise (Function.onFun AlmostDisjoint B))
+    (hbound : Bornology.IsBounded E) :
     Lebesgue_outer_measure E = Jordan_inner_measure E := by
   sorry
 
@@ -5121,7 +5122,8 @@ theorem IsOpen.eq_union_boxes {d:ℕ} (hd : 0 < d) (E: Set (EuclideanSpace' d))
         have h_scale_lt : (↑(B_idx j).1 : ℤ) < ↑(B_idx i).1 := by exact_mod_cast hij_gt
         exact dyadicCubeLargerNotInSmaller hd h_scale_lt h_ji
 
-theorem Lebesgue_outer_measure.of_open {d:ℕ} (E: Set (EuclideanSpace' d)) (hE: IsOpen E) : Lebesgue_outer_measure E = Jordan_inner_measure E := by
+theorem Lebesgue_outer_measure.of_open {d:ℕ} (E: Set (EuclideanSpace' d)) (hE: IsOpen E)
+    (hbound : Bornology.IsBounded E) : Lebesgue_outer_measure E = Jordan_inner_measure E := by
   by_cases hd : d = 0
   · -- Dimension 0: In dim 0, open sets are either ∅ or Set.univ
     subst hd
@@ -5255,7 +5257,7 @@ theorem Lebesgue_outer_measure.of_open {d:ℕ} (E: Set (EuclideanSpace' d)) (hE:
       -- Decompose E into almost-disjoint dyadic boxes
       obtain ⟨B, hE_eq, hB_dyadic, hB_disj⟩ := IsOpen.eq_union_boxes hd' E hE hE_nonempty
       -- Apply lemma eq_Jordan_inner_of_boxes (Exercise 1.2.5)
-      exact Lebesgue_outer_measure.eq_Jordan_inner_of_boxes E B hE_eq hB_disj
+      exact Lebesgue_outer_measure.eq_Jordan_inner_of_boxes E B hE_eq hB_disj hbound
 
 /-- Lemma 1.2.12 (Outer regularity). m\*(E) = inf\{m\*(U) : E ⊆ U, U open\}. -/
 theorem Lebesgue_outer_measure.eq {d:ℕ} (E: Set (EuclideanSpace' d)) : Lebesgue_outer_measure E = sInf { M | ∃ U, E ⊆ U ∧ IsOpen U ∧ M = Lebesgue_outer_measure U} := by
diff --git a/Analysis/Section_8_5.lean b/Analysis/Section_8_5.lean
index 4a3b64cb..34895e21 100644
--- a/Analysis/Section_8_5.lean
+++ b/Analysis/Section_8_5.lean
@@ -353,7 +353,14 @@ example : ¬ ∃ x : {x:ℝ| x > 0}, IsMin x := by sorry
 example {X Y:Type} [PartialOrder Y] (f:X → Y) : ∃ h₀: PartialOrder X, h₀.le = (fun x y ↦ f x < f y ∨ x = y) := by sorry
 
 def Ex_8_5_5_b : Decidable (∀ (X Y:Type) (h: LinearOrder Y) (f:X → Y), ∃ h₀: LinearOrder X, h₀.le = (fun x y ↦ f x < f y ∨ x = y)) := by
-  sorry
+  apply isFalse
+  intro H
+  let f : Bool → ℝ := fun _ ↦ 0
+  obtain ⟨inst, heq⟩ := H Bool ℝ inferInstance f
+  have htot := inst.le_total false true
+  -- With a constant map, the proposed `le` collapses to equality, which is not total on Bool.
+  rw [heq] at htot
+  simp [f] at htot
 
 -- Final part of Exercise 8.5.5; if the answer to the previous part is "no", modify the hypotheses to make it true.