##  [Extent](/extent) 

  ##  [Extent](https://puremath.quantumdictionary.io/extent-0) 

  

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- Mathematics & Logic -

**Pure Mathematics Dictionary**

 







 

 

 

 



 

 

 

 

Definition

The extent E(X) of a topological space X is the supremum of the cardinalities of closed discrete subspaces of X; equivalently, the largest cardinal κ such that X contains a closed discrete subset of cardinality κ.