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Viewing Version 2 of 'four-color conjecture'
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Title of object: four-color conjecture
Canonical Name: FourColorConjecture
Type: Theorem

Created on: 2003-01-04 21:52:15.764963-05
Modified on: 2003-01-04 21:53:17.87461-05

Creator: bbukh
Modifier: bbukh
Author: bbukh

Classification: msc:05C15, msc:05C10
Synonyms: four-color conjecture=Appel-Haken theorem
four-color conjecture=4-color conjecture

Revision comment (for changes between this and next version):

Changes for correction #1457 ('only only').
Added mention of Heawood number

Preamble:

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Content:

The four-color conjecture is a long-standing problem posed by Guthrie while coloring a map of England. The conjecture states that every map on a plane or a sphere can be colored using only only four colors such that no two adjacent countries are assigned the same color. This is equivalent to the statement that chromatic number of every planar graph is no more than four. After many unsuccessfull attempts the conjecture was proven by Appel and Haken in 1976 with an aid of computer.
\begin{thebibliography}{1}
\bibitem{cite:saaty_kainen_fcc}
Thomas~L. Saaty and Paul~C. Kainen.
\newblock {\em The Four-Color Problem: Assaults and Conquest}.
\newblock Dover, 1986.
\end{thebibliography}
%@BOOK{cite:saaty_kainen_fcc,
% author = {Thomas L. Saaty and Paul C. Kainen},
% title = {The Four-Color Problem: Assaults and Conquest},
% publisher = {Dover},
% year = 1986
%}