Absolute retract

Definition
A topological space is termed an absolute retract if it satisfies the following equivalent conditions:


 * Whenever it is embedded as a closed subspace of a normal space, it is a retract of that topological space
 * Given any normal space and a closed subspace, any map from the closed subspace to this space, extends to a map from the whole normal space to this space.

Weaker properties

 * Absolute neighbourhood retract