The Tasker Funeral Home confirms that Appel, who was diagnosed with esophageal cancer, died April 19 in hospice care.
Appel was a longtime educator who chaired the University of New Hampshire mathematics department, retiring in 2003.
Before that, he was a faculty member at the University of Illinois at Urbana. In 1976, he and Wolfgang Haken used 1,200 hours of calculations from an IBM computer to prove that a flat map can be colored with just four colors so that contiguous countries have different colors.
Proving the 100-year-old "Four-Color Conjecture" was considered a major intellectual accomplishment.
Read more at: http://phys.org/news/2013-04-kenneth-appel-dies.html#jCp
Appel was a longtime educator who chaired the University of New Hampshire mathematics department, retiring in 2003.
Before that, he was a faculty member at the University of Illinois at Urbana. In 1976, he and Wolfgang Haken used 1,200 hours of calculations from an IBM computer to prove that a flat map can be colored with just four colors so that contiguous countries have different colors.
Proving the 100-year-old "Four-Color Conjecture" was considered a major intellectual accomplishment.
Read more at: http://phys.org/news/2013-04-kenneth-appel-dies.html#jCp
The Tasker Funeral Home confirms that Appel, who was diagnosed with esophageal cancer, died April 19 in hospice care.
Appel was a longtime educator who chaired the University of New Hampshire mathematics department, retiring in 2003.
Before that, he was a faculty member at the University of Illinois at Urbana. In 1976, he and Wolfgang Haken used 1,200 hours of calculations from an IBM computer to prove that a flat map can be colored with just four colors so that contiguous countries have different colors.
Proving the 100-year-old "Four-Color Conjecture" was considered a major intellectual accomplishment.
Read more at: http://phys.org/news/2013-04-kenneth-appel-dies.html#jCp
Kenneth Appel est décédé le 19 Avril dernier. Membre du département de mathématiques Appel was a longtime educator who chaired the University of New Hampshire mathematics department, retiring in 2003.
Before that, he was a faculty member at the University of Illinois at Urbana. In 1976, he and Wolfgang Haken used 1,200 hours of calculations from an IBM computer to prove that a flat map can be colored with just four colors so that contiguous countries have different colors.
Proving the 100-year-old "Four-Color Conjecture" was considered a major intellectual accomplishment.
Read more at: http://phys.org/news/2013-04-kenneth-appel-dies.html#jCp
The Tasker Funeral Home confirms that Appel, who was diagnosed with esophageal cancer, died April 19 in hospice care.
Appel was a longtime educator who chaired the University of New Hampshire mathematics department, retiring in 2003.
Before that, he was a faculty member at the University of Illinois at Urbana. In 1976, he and Wolfgang Haken used 1,200 hours of calculations from an IBM computer to prove that a flat map can be colored with just four colors so that contiguous countries have different colors.
Proving the 100-year-old "Four-Color Conjecture" was considered a major intellectual accomplishment.
Read more at: http://phys.org/news/2013-04-kenneth-appel-dies.html#jCp
Appel was a longtime educator who chaired the University of New Hampshire mathematics department, retiring in 2003.
Before that, he was a faculty member at the University of Illinois at Urbana. In 1976, he and Wolfgang Haken used 1,200 hours of calculations from an IBM computer to prove that a flat map can be colored with just four colors so that contiguous countries have different colors.
Proving the 100-year-old "Four-Color Conjecture" was considered a major intellectual accomplishment.
Read more at: http://phys.org/news/2013-04-kenneth-appel-dies.html#jCp
de l'université du New Hampshire, il avait pris sa retraite en 2003
Il était auparavant en poste à l'Université de l'Illinois (Urbana). En 1976 il
avait démontré, avec Wolfgang Haken le théorème des quatre couleurs en
utilisant un ordinateur IBM pour venir à bout des derniers cas. Ce théorème dit qu'il suffit de
quatre couleurs pour colorier une carte de telle manière que deux pays voisins ne
soient pas de la même couleur. C'était la première preuve par ordinateur d'un théorème de mathématiques.
Ce résultat prouvait une conjecture qui avait résisté une centaine d'années.
Ce résultat a été prouvé en utilisant la théorie des graphes. Un graphe peut être associé à une
carte (voir le dessin ci-dessus, qui provient du blog http://mathyear2013.blogspot.fr/
et plus précisément d'un article sur le sujet du Prof. Hubbard). Le théorème revient alors à montrer
qu'un tel graphe peut être coloré avec seulement quatre couleurs de telle manière que deux
sommets reliés directement par une arête ne soient pas de la même couleur.
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