# Robin Wilson: Four colours suffice

**Abstract**:

In this talk I present the history and solution of the **four-colour problem**:

Can every map be coloured with just four colours so that neighbouring countries are coloured differently?

The answer is ‘yes’, but the proof took 124 years to find, and used 1200 hours of computer time. But what did it involve, and is it really a proof?

**Robin Wilson** is an Emeritus Professor of Pure Mathematics at the Open University, Emeritus Professor of Geometry at Gresham College, London, and a former Fellow of Keble College, Oxford University. A former President of the British Society for the History of Mathematics, he has written and edited over 50 books on the history of mathematics (including Lewis Carroll in Numberland and Euler’s Pioneering Equation) and on graph theory (including Introduction to Graph Theory and Four Colours Suffice). Involved with the popularization and communication of mathematics and its history, he has received awards from the Mathematical Association of America for his ‘outstanding expository writing’, and the Stanton Medal from the Institute of Combinatorics and its Applications for his outreach activities in combinatorics. He has been awarded two honorary doctorates and has Erdős Number 1.