The set of all the vertices adjacent to a given vertex.
The residential area near one's home.
The inhabitants of a residential area.
A formal or informal division of a municipality or region.
A set containing an open ball which contains a specified point.
The infinitesimal open set of all points that may be reached directly from a given point.
An approximate amount.
The quality of physical proximity.
A set containing an open set which contains some specified point.
Alternatively: An open ball which contains some specified point.
Alternatively: An open set which contains some specified point.