An ''n''-dimensional manifold (or ''n''-manifold) ''M'' is a [[topological space]] such that every point in ''M'' has a neighbourhood ''U'' that is [[homeomorphism|homeomorphic]] to ''R''<sup>''n''</sup>. The homeomorphisms <math>\phi_U : U\rightarrow \mathbf{R}^n</math> should be thought of as providing local coordinates in the neighborhood ''U''. Whenever two such coordinate neighborhoods ''U'' and ''V'' intersect, we also require that the change of coordinate maps <math>\phi_U\circ\phi_V^{-1}:\phi_V(U\cap V)\rightarrow \phi_U(U\cap V)</math> be homeomorphisms. | An ''n''-dimensional manifold (or ''n''-manifold) ''M'' is a [[topological space]] such that every point in ''M'' has a neighbourhood ''U'' that is [[homeomorphism|homeomorphic]] to ''R''<sup>''n''</sup>. The homeomorphisms <math>\phi_U : U\rightarrow \mathbf{R}^n</math> should be thought of as providing local coordinates in the neighborhood ''U''. Whenever two such coordinate neighborhoods ''U'' and ''V'' intersect, we also require that the change of coordinate maps <math>\phi_U\circ\phi_V^{-1}:\phi_V(U\cap V)\rightarrow \phi_U(U\cap V)</math> be homeomorphisms. |