Manifolds With Boundary
A slightly more general concept is sometimes useful. A topological manifold with boundary is a Hausdorff space in which every point has a neighborhood homeomorphic to an open subset of Euclidean half-space (for a fixed n):
The terminology is somewhat confusing: every topological manifold is a topological manifold with boundary, but not vice-versa.
Read more about this topic: Topological Manifold
Famous quotes containing the word boundary:
“The boundary line between self and external world bears no relation to reality; the distinction between ego and world is made by spitting out part of the inside, and swallowing in part of the outside.”
—Norman O. Brown (b. 1913)