There is very nice webpage at
http://www.math.gatech.edu/~thomas/FC/fourcolor.html
which provides, among other titbits, a brief summary of a new proof of
the Four Color Theorem, and a four-coloring algorithm found by Neil
Robertson, Daniel P. Sanders, Paul Seymour, and Robin Thomas.
Table of Contents:
1. History.
2. Why a new proof?
3. Outline of the proof.
4. Main features of our proof.
5. Configurations.
6. Discharging rules.
7. Pointers.
8. A quadratic algorithm.
9. Discussion.
10. References.
It'll surely be of your interest.
Greetings from Montevideo,
Julio GC
PS. There are tons of material relative to the 4CP on the Net.
Paper references:
[1] Appel, K. and Haken, W.:
"Every planar map is four colorable. I: Discharging", Illinois J. Math.
21, 429-490, 1977.
[2] "Every planar map is four colorable. II: Reducibility", Illinois J.
Math. 21, 491-567, 1977.
[3] Appel, K. and Haken, W.:
"The Solution of the Four-Color Map Problem", Sci. Amer. 237, 108-121, 1977.
[4] Appel, K. and Haken, W.:
"Every Planar Map is Four-Colorable", Providence, RI: American
Mathematical Society, 1989. This book is *on sale* (Sale Price: USD 47,
list price USD 94!). It contains corrected versions of the two papers
[1] and [2], and bits of the history of the Four-Color Problem.
At 07:07 PM 05/02/1999 -0500, Sam Kutler wrote:
| Is there a website that gives information on the 4-color problem including
| the solution by Appel & Haken?