# Category:Neighborhoods

This category contains results about Neighborhoods.
Definitions specific to this category can be found in Definitions/Neighborhoods.

Let $A \subseteq S$ be a subset of $S$.

A neighborhood of $A$, which can be denoted $N_A$, is any subset of $S$ containing an open set of $T$ which itself contains $A$.

That is:

$\exists U \in \tau: A \subseteq U \subseteq N_A \subseteq S$

## Subcategories

This category has the following 2 subcategories, out of 2 total.