### DIMACS - Graduate Student Combinatorics Seminar

Title: Colorblind: Alfred Kempe and the Four-Color Theorem

Speaker: **John Chiarelli**, Rutgers University

Date: Wednesday, February 18, 2015 12:10pm

Location: Graduate Student Lounge, 7th Floor, Hill Center, Rutgers University, Busch Campus, Piscataway, NJ

Abstract:

When Kenneth Appel and Wolfgang Haken revealed their proof of the Four-Color Theorem in 1976, they were met with a lot of skepticism, and not just because of their use of computers. The Four-Color Theorem - which states that any planar graph can be colored with four colors such that no two adjacent vertices are the same color - has a long history of failed attempts at a solution. In this talk, I will look into the details of one particular failed attempt at proving the theorem, posited by Alfred Kempe in 1879. While it ultimately turned out to be incorrect, the methods used have notable applications. Accompanying this "proof" will be Percy James Heawood's modifications to Kempe's work to prove a weaker proof, the Five-Color Theorem.

Further information can be found at http://math.rutgers.edu/~nhf12/GCS/