Theorem
Let
be one to one continuous function
from a compact space
into a Hausdorff space![]()

is homeomorphic to![]()
Proof
is a continuous bijection, hence one to one and onto. Hence
exists and is well defined.
is continuous if, for every closed subset
of![]()
is a closed subset of![]()
Let
be a closed subset of a compact space, then
is compact. Since
is continuous
is a compact subset of![]()
is Hausdorff, since it is a subspace of a Hausdorff space, hence
is closed and
is continuous.
Hence
is a homeomorphism.