Chapter 2: Graphs and Networks Lesson 2: Hello Mr Euler… Discrete Maths Chapter 2: Graphs and Networks Lesson 2: Hello Mr Euler…
Where graph theory came from…
Where graph theory came from…
Let’s learn some definitions…
Trail (or route)
Closed Trail
Path
Cycle
Order
Connected Graph
Eulerian Graph A connected graph which has a closed trail containing every arc precisely once A B C D A B C D E √ X CHECK: A connected graph is Eulerian if and only if every node has an even order
A wee puzzle… F D B C E A
Semi-Eulerian Graph A graph which has a trail that is not closed that contains every arc precisely once F D B C E A CHECK: A connected graph is Semi-Eulerian if and only if precisely two nodes have odd order