Theorem
Letbe the set of components of a space
The components of
form a partition of
i.e.
and
if
Proof
Any elementbelongs to at least one connected subspace i.e. at least one of the
All the
are connected. If
for any
then x would have to be in some other connected subspace
But then
- a contradiction. Hence
for some
Take two setsand
Suppose
and
Then
is a connected subset of
containing both
and
- a contradiction since
if