## Four Color Fest

To celebrate the 40th anniversary of the proof of the Four Color Theorem, and as a part of the 2017 sesquicentennial celebration of the founding of the University of Illinois, the Illinois Mathematics Department will hold a Four Color Fest. This event, to be held November 2-4, 2017, will be a multi-day event celebrating the mathematical, historical and cultural significance of Appel and Hakenâ€™s achievement.

Public lectures on the Four Color Theorem will be given by Andrew Appel and Robin Wilson. Andrew Appel is Eugene Higgins Professor of Computer Science at Princeton University and a well-known expert on machine verification of formal proofs. Robin Wilson, Professor Emeritus of Pure Mathematics at the Open University and at Gresham College, London, is former President of the British Society for the History of Mathematics and author of the popular science book Four Colours Suffice: How the Map Problem was Solved.

#### Schedule of Events

**Thursday, November 2, 2017**

- 4 pm, 314 Altgeld Hall

Lecture:**Robin Wilson**(Professor Emeritus of Pure Mathematics at the Open University and at Gresham College, London) - 5-6 pm Reception, 239 Altgeld Hall

**Friday, November 3, 2017 **

- 4 pm, Spurlock Museum Auditorium

Lecture:**Andrew Appel**(Eugene Higgins Professor of Computer Science at Princeton University) - 5-7 pm,
Ballroom, Alice Campbell Alumni Center

Reception

**Saturday, November 4, 2017**

- 10 am - noon, 239 Altgeld Hall

Illinois Geometry Lab hosts an**open house**with Four Color Theorem-related activities for K-12 students and community. - 7:30 pm, Music Building Auditorium

Music performance by**Rudolf Haken**(internationally renowned violist and composer, and Associate Professor of Music at the University of Illinois) and**Rob Schwimmer**(composer-pianist/keyboardist, New York)

#### Four Color Theorem

In 1976, two mathematicians at the University of Illinois, Kenneth Appel and Wolfgang Haken, announced the solution to the Four Color Problem. Originally posed by Francis Guthrie in 1852, the Four Color Problem conjectures that four is the smallest number of colors needed to color the regions of an arbitrary map in such a manner that any two adjacent countries are painted with different colors.

Appel and Haken’s resolution of the Four Color Problem was remarkable both for its mathematical and historical significance as the solution to a long-standing problem with an extremely simple formulation, and also for the method of proof. In fact their proof, which made extensive use of computing technology, was the first mathematical proof to rely in an essential fashion on the use of computers.

Published in 1977 in the Illinois Journal of Mathematics, the Appel-Haken Four Color Theorem is one of the signature achievements of the University of Illinois Department of Mathematics and a landmark result in geometry, graph and network theory, and computer science.