Colouring

Maps and schedules

An interactive lesson with 6 steps, about 5 minutes: you predict, drag and solve, with instant feedback on every answer. It runs in your browser and needs JavaScript.

What you’ll learn

• Graph colouring: adjacent vertices get different colours.
• Odd cycles need 3 colours. Every flat map needs at most 4 (the four colour theorem).
• Timetables and frequency assignments are colouring problems.

Steps

1. Colour the pentagon
2. Add a hub
3. The four colour theorem
4. Two colours?
5. The Petersen graph
6. Exam timetable