Category:Definitions/Bounded Variation

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This category contains definitions related to Bounded Variation.
Related results can be found in Category:Bounded Variation.

Definition

Closed Bounded Interval

For each finite subdivision $P$ of $\closedint a b$, write:

$P = \set {x_0, x_1, \ldots, x_n}$

with:

$a = x_0 < x_1 < x_2 < \cdots < x_{n - 1} < x_n = b$

Also write:

$\ds \map {V_f} {P ; \closedint a b} = \sum_{i \mathop = 1}^n \size {\map f {x_i} - \map f {x_{i - 1} } }$


We say $f$ is of bounded variation if and only if there exists an $M \ge 0$ such that:

$\map {V_f} {P ; \closedint a b} \le M$

for all finite subdivisions $P$.


Closed Unbounded Interval

For each finite non-empty subset $\mathcal S$ of $I$, write:

$\mathcal S = \set {x_0, x_1, \ldots, x_n}$

with:

$x_0 < x_1 < x_2 < \cdots < x_{n - 1} < x_n$

Also write:

$\ds \map {V_f^\ast} {\mathcal S; I} = \sum_{i \mathop = 1}^n \size {\map f {x_i} - \map f {x_{i - 1} } }$

for $n \ge 1$, and $\map {V_f^\ast} {\mathcal S ; I} = 0$ otherwise.


We say $f$ is of bounded variation if and only if there exists an $M \ge 0$ such that:

$\map {V_f^\ast} {\mathcal S; I} \le M$

for all finite non-empty subsets $\mathcal S$ of $I$.


Also known as

Some sources say that $f$ is of finite variation rather than bounded variation.


Sources