Labelled Graphs

• Vertices and vertex labels
• Edges and edge labels

For now, simple graphs.

A graph G consists of a set of vertices V and a set of edges E such that
(u,v) $\in$ E $\rightarrow$ u, v $\in$ V and u is connected to v with an edge.

Directed edge: u $\rightarrow$ v
Undirected edge: u -- v