Absolute retract
This article defines a property of topological spaces: a property that can be evaluated to true/false for any topological space|View a complete list of properties of topological spaces
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.