Definition:Boundary (Topology)/Notation

Notation
The boundary of $H$ is variously denoted (with or without the brackets):
 * $\partial H$
 * $\map {\operatorname b} H$
 * $\map {\operatorname {Bd} } H$
 * $\map {\operatorname {fr} } H$ (where $\operatorname {fr}$ stands for frontier)
 * $H^b$

The notations of choice on are $\partial H$ and $H^b$.