Linked from

The 3 pages that link to Lebesgue density theorem, each with the reason it gives.

• Lebesgue differentiation theoremRelated: It follows by applying differentiation to the set’s indicator function.

• Vitali covering theoremRelated: Vitali coverings help show that points failing the density conclusion form a null set.

• Denjoy–Luzin theoremRelated: Density points turn measure-theoretic control of value sets into approximate continuity.