Chapter 2 - Graphs and Networks

• Degree/Valency/Order = Number of edges from a node
• Walk = Route along edges from 1 vertex to another
• Path = Walk where no vertex is visited more than once
• Trail = Walk where no edge is visited more than once
• Cycle = A path which starts and finishes at the same vertex
• Di-graph = A graph with edges that can only be traversed one way
• Euler's Handshaking Lemma = Sum of the degrees of vertices is equal to 2x the number of edges
• Planar Graph = A graph which can be drawn in a way so that no 2 edges cross except at 2 vertices