A function $f: [a,b]\to \mathbb R$ is of bounded variation if for every partition of a set $P ={a= x_0 < <x_1 < \cdots < x_n = b}$, we have \(\sup_P \sum_{i=1}^n \vert f(x_i)-f(x_{i-1})\vert <\infty.\)
Wikidata ID: Q829653