Ore, Oystein (1899–1968)

Norwegian mathematician whose work concentrated on the fields of abstract algebra, number theory, and the theory of graphs.

Ore was born in Christiania (now Oslo), and studied at Oslo University, briefly visiting the University of Göttingen, Germany, where he was influenced by mathematician Emmy Noether. In 1926 he became professor at Oslo, but moved a year later to Yale in the USA. In 1945 he returned to Norway.

Ore investigated linear equations in noncommutative fields, summarizing his work in a book on abstract algebra in 1936. He then turned to an examination of number theory, and in particular of algebraic numbers.

Ore also wrote a book (1967) on the four-colour problem, the theory that maps require no more than four colours for each region of the map to be coloured but with no zone sharing a common border with another zone of the same colour. German mathematician August Möbius had raised this problem in 1840.