##  [Caliber](/caliber) 

  ##  [Caliber](https://puremath.quantumdictionary.io/caliber-0) 

  

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- Mathematics & Logic -

**Pure Mathematics Dictionary**

 







 

 

 

 



 

 

 

 

Definition

A cardinal κ is a caliber (calibre) of a topological space X if every family of κ nonempty open sets in X contains a subfamily of size κ whose intersection is nonempty. Variants consider countable caliber, calibers relative to directed families, or requiring finite intersections.