RIEMANN

GERMANY (see also List of Individuals)

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17.9.1826 Breselenz/D - 20.7.1866 Selasca/I

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Bernhard Riemann was the son of a clergyman. He initiated studies in 1846 in theology and philology at Göttingen University, but turned to mathematics soon. One year later he moved to Berlin University and submitted in 1850 in Göttingen a thesis on the theory of functions with a complex variable. This work was praised by Gauss and led the foundations for his work in the following decade. In 1859 he moved to Göttingen, where Gauss had been a professor until 1855. The struggle to survive on the casual fees of a private teacher had undermined his health such that he passed away at age 40.

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Riemann introduced in mathematics the many-leafed Riemann surfaces whose sheets are connected around the branch-points of the function, on which the latter can be defined as single value. He demonstrated how to treat the function as a conformal map of a simply connected domain, described essentially by the point singularities of the function and the shape of the map along the boundary of the domain. He also laid the foundations to the non-Euclidian geometry. Throughout this subject he was motivated by his studies in mathematical physics. In hydromechanics, Riemann computed twodimensional outflow from a large tank by the hodograph method, and determined the contraction coefficient from an infinitely small orifice. His method was generalized by Richard von Mises (1883-1953) some fifty years later and served as a starting point of plane inviscid flow analyses in the 20th century. Riemann also worked on propagation characteristics of waves in the air.

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_{Jaggi, M.P. (1967). The visionary ideas of Bernhard Riemann. Physics Today 20(12): 42-45. P}

_{Patten, P.R. (1999). Bernhard Riemann. Biographical encyclopedia of mathematicians 2: 451-}

_{454. Marshall Cavendish: New York. P}

_{Poggendorff, J.C. (1863). Riemann, Georg Friedrich Bernhard. Biographisch-Literarisches Handwörterbuch 2: 641. Barth: Leipzig, with bibliography.}

_{Riemann, B. (1858). Über die Fortpflanzung ebener Luftwellen von endlicher Schwingungsweite. Abhandlungen Königliche Gesellschaft der Wissenschaften Göttingen, Mathematisch-Physikalische Klasse 8: 43-65.}

_{Riemann, B. (1953). Collected works, H. Weber, ed. Dover: New York. P}

_{Tricomi, F.G. (1965). Bernhard Riemann e l'Italia. Rendiconti dell Seminario Matematico}

_{Torino 25: 59-72. P}

_{Werckmeister, K. (1901). Bernhard Riemann. Das 19. Jahrhundert in Bildnissen: 557.}

_{Kunstverlag Photographische Gesellschaft: Berlin. P}