##  [Reach](/index.php/reach) 

  ##  [Reach](https://puremath.quantumdictionary.io/reach-0) 

  

 [![Pure Mathematics Dictionary](/sites/default/files/styles/large/public/2026-01/Pure%20Mathematics.png.webp?itok=5pZnFQ59)](/index.php/topic-specific-dictionaries/mathematics-logic/pure-mathematics)

- Mathematics & Logic -

**Pure Mathematics Dictionary**

 







 

 

 

 



 

 

 

 

Definition

For a closed subset A of Euclidean space, the reach is the supremal r≥0 such that every point at distance less than r from A has a unique nearest point in A; equivalently the radius of the largest tubular neighborhood on which the nearest-point projection is well-defined and single-valued.

 

 

 

 

 





 

 



 ##  [Reach](https://information.quantumdictionary.io/reach-1) 

  

 [![Information & Communication Dictionary](/sites/default/files/styles/large/public/2026-01/Information%20%26%20Communication.png.webp?itok=g4emS-T7)](/index.php/topic-specific-dictionaries/information-communication)



**Information & Communication Dictionary**

 







 

 

 

 



 

 

 

 

Definition

The count of unique individuals (or deduplicated audience units) who have been exposed to a particular media item, campaign or publication within a specified time frame; reach emphasizes breadth of exposure rather than frequency and is typically measured by deduplicating audiences across channels using deterministic identifiers or probabilistic models.