Möbius, August Ferdinand (1790–1868)

German mathematician and theoretical astronomer, discoverer of the Möbius strip and considered one of the founders of topology.

Möbius formulated his barycentric calculus in 1818, a mathematical system in which numerical coefficients were assigned to points. The position of any point in the system could be expressed by varying the numerical coefficients of any four or more noncoplanar points.

Möbius was born near Naumburg and studied at Leipzig and Göttingen. From 1815 he was on the staff at Leipzig, where he became professor of astronomy and higher mechanics in 1844 and director of the observatory in 1848.

In addition to the Möbius strip, he discovered the Möbius net, later of value in the development of projective geometry; the Möbius tetrahedra, two tetrahedra that mutually circumscribe and inscribe each other, which he described in 1828; and the Möbius function in number theory, published in 1832.

During a lecture of 1840, Möbius set the problem to find the least number of colours required on a plane map to distinguish political regions, given that each boundary line should separate two differently coloured regions. It has now been proved by computer analysis that four colours will always suffice.