Topics: Graph Theory
In a graph, the points that represent elements are called vertices or nodes. The set of vertices in a graph, commonly denoted by , must be non-empty.
Adjacency and Neighbours
When a vertex is joined to another vertex by means of an edge, we say that they’re adjacent and that is a neighbour of .
An isolated vertex is a vertex with degree 0.
A hanging vertex is a vertex with degree 1.