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  1. Cover (topology) - Wikipedia

    • The cover is said to be an open cover if each of its members is an open set. That is, each is contained in , where is the topology on X). [1] A simple way to get a subcover is to omit the sets contained in another set in the cover. Consider specifically open covers. See more

    Overview

    In mathematics, and more particularly in set theory, a cover (or covering) of a set is a family of subsets of whose union is all of . … See more

    Definition

    Covers are commonly used in the context of topology. If the set is a topological space, then a cover of is a collection of subsets of whose union is the whole space . In this case is said to cover , or that the sets cover .
    If is … See more

    Refinement

    A refinement of a cover of a topological space is a new cover of such that every set in is contained in some set in . Formally,
    is a refinement of if for all there exists such that
    In other wo… See more

    Compactness

    The language of covers is often used to define several topological properties related to compactness. A topological space is said to be:
    compact if every open cover has a finite subcover, (… See more

    Covering dimension

    A topological space X is said to be of covering dimension n if every open cover of X has a point-finite open refinement such that no point of X is included in more than n+1 sets in the refinement and if n is the minimum v… See more

    See also

    Atlas (topology) – Set of charts that describes a manifold
    Bornology – Mathematical generalization of boundedness
    Covering space – Type of continuous map in topology… See more