Definition:Boundary (Topology)

Definition
Let $T = \struct {S, \tau}$ be a topological space.

Let $H \subseteq S$.

Also known as
The boundary of a subset $H$ is also seen referred to as the frontier of $H$.

Also see

 * Equivalence of Definitions of Boundary


 * Boundary is Intersection of Closure with Closure of Complement


 * Definition:Boundary (Geometry)