A function $f:[a,b]\to \mathbb R^n$ is absolutely continuous if for every $\varepsilon > 0$, there exists $\delta > 0$ such that if ${(x_i,y_i)}_{i=1}^k$ are pairwise disjoint subintervals of $[a,b]$ with total combined length less than $\delta$, then \(\sum_{i=1}^k \vert f(y_i) - f(x_i)\vert < \varepsilon.\) Wikidata ID: Q332504