neighborhood retract

Let $X$ be a topological space and $Y$ a subspace of $X$. If there exists an open set $U$ such that $Y\subset U\subset X$ and $Y$ is a retract of $U$, then we say $Y$ is a neighborhood retract of $X$.

Title	neighborhood retract
Canonical name	NeighborhoodRetract
Date of creation	2013-03-22 14:39:41
Last modified on	2013-03-22 14:39:41
Owner	rspuzio (6075)
Last modified by	rspuzio (6075)
Numerical id	5
Author	rspuzio (6075)
Entry type	Definition
Classification	msc 54A99