Hereditarily collectionwise normal space: Difference between revisions

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==Definition==
==Definition==


A [[topological space]] is termed '''hereditarily collectionwise normal''' if every subspace of it is [[collectionwise normal space|collectionwise normal]].
A [[topological space]] is termed '''hereditarily collectionwise normal''' or '''completely collectionwise normal''' if it satisfies the following two conditions:
 
# every subspace of it is [[collectionwise normal space|collectionwise normal]]
# every almost discrete collection of closed subsets can be separated by pairwise disjoint open subsets (here, ''almost discrete'' means discrete in the union).


==Formalisms==
==Formalisms==

Latest revision as of 00:15, 25 October 2009

This article defines a property of topological spaces: a property that can be evaluated to true/false for any topological space|View a complete list of properties of topological spaces

This is a variation of normality. View other variations of normality

Definition

A topological space is termed hereditarily collectionwise normal or completely collectionwise normal if it satisfies the following two conditions:

  1. every subspace of it is collectionwise normal
  2. every almost discrete collection of closed subsets can be separated by pairwise disjoint open subsets (here, almost discrete means discrete in the union).

Formalisms

In terms of the hereditarily operator

This property is obtained by applying the hereditarily operator to the property: collectionwise normal space

Relation with other properties

Stronger properties

Weaker properties

Metaproperties

Hereditariness

This property of topological spaces is hereditary, or subspace-closed. In other words, any subspace (subset with the subspace topology) of a topological space with this property also has this property.
View other subspace-hereditary properties of topological spaces