Definition:Niemytzki Plane

Definition
The Niemytzki plane is the topological space $T = \struct {S, \tau}$ defined as:

where $\map {B_r} {x, y}$ denotes the open $r$-ball of $\tuple {x, y}$ in the $\R^2$ Euclidean space.

Also known as
The Niemytzki plane can also be rendered as Nemytskii plane, as the name of its creator can be rendered in Latin characters in different ways.

It can also be referred to as:
 * Nemytskii's tangent disk topology
 * The Moore plane, after.

Also see

 * Niemytzki Plane is Topology