In the late 1990s, Neil Robertson and Paul Seymour gave another proof of this result that was streamlined since they only had to show D-reducibility and C-reducibility.
In the late 1990s, Neil Robertson and Paul Seymour gave another proof of this result that was streamlined since they only had to show D-reducibility and C-reducibility. In the 19th century, Alfred Kempe gave a flawed proof of this result, though his work using his namesake Kempe chains were also used in the first correct proof of it. This result relied on the method of discharging developed by Heinrich Heesch. A computer at the University of Illinois took thousands of hours to check through 1,476 cases of graphs devised by Kenneth Appel and Wolfgang Haken as part of the first correct proof for this theorem. For 10 points, name this theorem that states that all regions of a planar map can be assigned a hue using at most the namesake number of hues.
In the late 1990s, Neil Robertson and Paul Seymour gave another proof of this result that was streamlined since they only had to show D-reducibility and C-reducibility.
four-color theorem