Let , be topological spaces. A map is said to be an embedding (or imbedding) if the restriction is homeomorphism.
The notation is often used for embeddings.
The embeddings correspond to the subspaces. Observe that and the inclusion map of the subspace into differ only up to a homeomorphism.
![$ f:X\to f[X]$](http://images.planetmath.org:8080/cache/objects/7385/l2h/img4.png "$ f:X\to f[X]$"){kind=small}
![$ f[X]$](http://images.planetmath.org:8080/cache/objects/7385/l2h/img7.png "$ f[X]$"){kind=small}
