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fix: restore determinant scaling factor to measure_linear #636

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fix: restore determinant scaling factor to measure_linear #636

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2 changes: 1 addition & 1 deletion Analysis/MeasureTheory/Section_1_1_2.lean
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Expand Up @@ -735,7 +735,7 @@ lemma JordanMeasurable.linear {d:ℕ} (T: EuclideanSpace' d ≃ₗ[ℝ] Euclidea
/-- Exercise 1.1.11 (2) -/
-- The measure of a linear image of a Jordan measurable set equals the original measure (up to determinant scaling).
lemma JordanMeasurable.measure_linear {d:ℕ} (T: EuclideanSpace' d ≃ₗ[ℝ] EuclideanSpace' d) :
∃ D > 0, ∀ (E: Set (EuclideanSpace' d)) (hE: JordanMeasurable E), (linear T hE).measure = hE.measure := by sorry
∃ D > 0, ∀ (E: Set (EuclideanSpace' d)) (hE: JordanMeasurable E), (linear T hE).measure = D * hE.measure := by sorry

/-- An invertible matrix defines a linear equivalence on Euclidean space. -/
noncomputable def Matrix.linear_equiv {d:ℕ} (A: Matrix (Fin d) (Fin d) ℝ) [Invertible A] :
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