four-colour theorem
It's one of mathematics' most famous results: every "map" can be coloured using at most four colours. What it doesn't usually apply to, however, are real maps.
Asking good questions is an important part of doing maths. But what makes a good question?
The new Maths KTN is showing business how to do mathematics and mathematics how to do business.
Robert Hunt concludes our Origins of Proof series by asking what a proof really is, and how we know that we've actually found one. One for the philosophers to ponder...