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locally finite collection (Definition)

Let $\mathcal{C}$ be a collection of subsets of a topological space $X$

$\mathcal{C}$ is said to be locally finite if for all $x\in X$ there is a neighbourhood $U$ of $x$ such that $U \cap A = \varnothing$ for all but finitely many $A \in \mathcal{C}$

Similarly, $\mathcal{C}$ is said to be locally countable if for all $x\in X$ there is a neighbourhood $U$ of $x$ such that $U \cap A = \varnothing$ for all but countably many $A \in \mathcal{C}$




"locally finite collection" is owned by yark. [ full author list (2) | owner history (1) ]
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See Also: point finite

Also defines:  locally finite, locally countable collection, locally countable
Keywords:  topology

Attachments:
the union of a locally finite collection of closed sets is closed (Theorem) by yark
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Cross-references: neighbourhood, topological space, subsets, collection
There are 8 references to this entry.

This is version 7 of locally finite collection, born on 2002-01-22, modified 2008-10-03.
Object id is 1542, canonical name is LocallyFinite.
Accessed 5040 times total.

Classification:
AMS MSC54D20 (General topology :: Fairly general properties :: Noncompact covering properties )

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