# Open Domain is Connected iff it is Path-Connected

## Theorem

Let $D \subseteq \C$ be a open subset of the set of complex numbers.

Then $D$ is connected if and only if $D$ is path-connected.

## Proof

### Necessary Condition

Complex Plane is Metric Space shows that $\C$ is topologically equivalent to the Euclidean space $\R^2$.

The result follows from Connected Open Subset of Euclidean Space is Path-Connected.

$\Box$

### Sufficient Condition

The result follows from Path-Connected Space is Connected.

$\blacksquare$