Local homeomorphism

A mapping between topological spaces such that for every point there is a neighbourhood that maps homeomorphically into under (cf. Homeomorphism). Sometimes in the definition of a local homeomorphism the requirement is included and is also assumed to be open (cf. Open mapping). Examples of local homeomorphisms are: a continuously-differentiable mapping with non-zero Jacobian on an open subset of an -dimensional Euclidean space into the -dimensional Euclidean space; a covering mapping, in particular the natural mapping of a topological group onto its quotient space with respect to a discrete subgroup. If the mapping of a Čech-complete space, in particular a locally compact Hausdorff space, onto a Tikhonov space is open and countable-to-one, that is, , , then on some open everywhere-dense set in the mapping is a local homeomorphism.

References

[a1]	A.V. Arkhangel'skii, V.I. Ponomarev, "Fundamentals of general topology: problems and exercises" , Reidel (1984) (Translated from Russian)