John Rolfe Isbell (October 27, 1930 – August 6, 2005)[1] was an American mathematician. For many years he was a professor of mathematics at the University at Buffalo (SUNY).
Isbell published over 140 papers under his own name, and several others under pseudonyms. Isbell published the first paper by John Rainwater, a fictitious mathematician who had been invented by graduate students at the University of Washington in 1952. After Isbell's paper, other mathematicians have published papers using the name "Rainwater" and have acknowledged "Rainwater's assistance" in articles.[8] Isbell published other articles using two additional pseudonyms, M. G. Stanley and H. C. Enos, publishing two under each.[4][8]
In geometric graph theory, Isbell was the first to prove the bound χ ≤ 7 on the Hadwiger–Nelson problem, the question of how many colors are needed to color the points of the plane in such a way that no two points at unit distance from each other have the same color.[13]
^The University of Kansas had professors Ainsley Diamond and Nachman Aronszajn, who had previously been professors at Oklahoma A&M. The two moved to Kansas after Oklahoma A&M had instituted a requirement that instructors sign a strict loyalty oath. Ainsley Diamond, as a quaker, had refused to sign the loyalty oath.