Definition:Subdivision (Real Analysis)



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This page is about Subdivision in the context of Real Analysis. For other uses, see Subdivision.

  • 1.2 Infinite
  • 2 Normal Subdivision
  • 3 Higher Dimensions
  • 4 Also known as
  • 5 Sources
  • Definition

    Let $\closedint a b$ be a closed interval of the set $\R$ of real numbers.


    Finite

    Let $x_0, x_1, x_2, \ldots, x_{n - 1}, x_n$ be points of $\R$ such that:

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


    Then $\set {x_0, x_1, x_2, \ldots, x_{n - 1}, x_n}$ form a finite subdivision of $\closedint a b$.


    Infinite

    Let $x_0, x_1, x_2, \ldots$ be an infinite numberofpoints of $\R$ such that:

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


    Then $\set {x_0, x_1, x_2, \ldots}$ forms an infinite subdivision of $\closedint a b$.


    Normal Subdivision

    $P$ is a normal subdivision of $\closedint a b$ if and only if:

    the length of every interval of the form $\closedint {x_i} {x_{i + 1} }$ is the same as every other.


    That is, if and only if:

    $\exists c \in \R_{> 0}: \forall i \in \N_{< n}: x_{i + 1} - x_i = c$


    Higher Dimensions

    Rectangle

    Let $R = \closedint {a_1} {b_1} \times \dotso \times \closedint {a_n} {b_n}$ be a closed rectangle in $\R^n$.

    Let:

    $P = \tuple {P_1, \dotsc, P_n}$

    where every $P_i$ is a finite subdivision of $\closedint {a_i} {b_i}$.


    Then $P$ is a finite subdivision of the closed rectangle $R$.


    Also known as

    Some sources use the term partition for the concept of a subdivision.

    However, the latter term has a different and more general definition, so its use is discouraged on $\mathsf{Pr} \infty \mathsf{fWiki}$.

    Some use the term dissection, but again this also has a different meaning, and is similarly discouraged on $\mathsf{Pr} \infty \mathsf{fWiki}$.


    Sources

    Retrieved from "https://proofwiki.org/w/index.php?title=Definition:Subdivision_(Real_Analysis)&oldid=642118"

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    Definitions/Subdivisions (Real Analysis)



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