Absolute continuity

Absolute continuity is a concept from real analysis that extends the idea of continuity and provides a stronger form of integration. A function \( f \) defined on an interval \([a, b]\) is said to be absolutely continuous if it satisfies the following criteria: 1. **Existence of a Derivative**: For almost every point \( x \in [a, b] \), the function \( f \) has a derivative \( f'(x) \).