Some mathematicians were reluctant to accept the proof of the four-color problem because of the necessity of computer verification.

The proof was not “elegant” in the sense that it required the computer analysis of a large number of cases. Study the map in Figure 9.50 and determine for yourself whether it is the first five-color map, providing a counterexample for the computerized

“proof.” Figure 9.50

What is the color of the white region? Consider the following table:

Transcribed Image Text:

2 (green) 4 (blue) 1 (red) 5 (yellow) 3 (red) 6 (blue) ? 6 (blue) 7 (yellow)