Category:Definitions/Open Regions of Complex Plane

This category contains definitions related to Open Regions of Complex Plane.
Related results can be found in Category:Open Regions of Complex Plane.

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

$D$ is an open region of $\C$ if and only if $D$ is:

$(1): \quad$ An open set

and

$(2): \quad$ connected.