The book is now available! 7
(another Prime Pages' Curiosity)
Prime Curios!
Curios: Curios Search:

Single Curio View:   (Seek other curios for this number)


Graph theorists have been able to prove that 7 colors are required on a donut-shaped map (i.e., an ordinary one-holed torus) to ensure that no adjacent areas are the same.


  Submitted: 1999-09-02 18:40:00;   Last Modified: 2009-08-15 06:38:05.

Prime Curios! © 2000-2018 (all rights reserved)