Graph vertex

A vertex (or node) in graph theory is a part of a graph that edges connect to.

They can represent various different things depending on what the graph is used to represent.

Degree of a vertex

The degree of a vertex is the number of edges connected to it.

For example, if a vertex has 3 edges connected to it, its degree is 3.

Degree in directed graphs

In a directed graph, we distinguish between:

• In-degree: The number of edges coming into the vertex.
• Out-degree: The number of edges going out from the vertex.