# Four Colours Suffice?

- Institution: Gresham College
- Speaker: Professor Robin Wilson
- Year: 2002
- Level: For everyone
- Language: English
- Subjects: Mathematics, History
- Source: [Gresham College](https://www.gresham.ac.uk/watch-now/four-colours-suffice)
- Licence: [Educational use (Gresham College's terms)](https://www.gresham.ac.uk/terms-and-conditions)
- Who can watch: Teens profiles and older (sources give no ratings; placed by Invisible Network from the source's own words)

How many colours are needed to colour a map so that neighbouring countries are coloured differently? At first it seems that for very complicated maps, many colours are needed, but surprisingly four colours suffice for all maps - a fact that took over a hundred years to prove. In this lecture we commemorate the 150th anniversary of this famous problem by outlining its history and solution. The eventual proof, making extensive use of a computer, raises some interesting philosophical questions.

## Lectures

1. [Four Colours Suffice?](https://invisiblenetwork.ai/learn/gresham/four-colours-suffice/1ba03f670710) (YouTube)