GERMAIN, SOPHIE

born April 1, 1776, Paris, France died June 27, 1831, Paris in full Marie-sophie Germain French mathematician who contributed notably to the study of acoustics, elasticity, and the theory of numbers. Her most fruitful contribution was the limited proof of Fermat's last theorem for the case in which x, y, z are not divisible by an odd prime, p; the theorem states that there is no solution for the equation xn + yn = zn if n is an integer greater than 2, and x, y, and z are nonzero integers. The theorem was proved for all cases by the English mathematician Andrew Wiles in 1995. Germain read widely in her father's library. Having mastered calculus by studying what books she could obtain, Germain took correspondence courses from the cole Polytechnique, Paris, which did not allow women in the school itself. In 1811, 1813, and 1816 she presented three theoretical memoirs on the German physicist Ernst F.F. Chladni's experimental findings on vibrating plates. The last memoir was awarded a prize by the Institut de France. Sophie Germain was a friend of the eminent mathematicians Joseph-Louis Lagrange of France and Carl Friedrich Gauss of Germany, with whom she corresponded under the pseudonym M. Leblanc before revealing her identity. She was so highly esteemed by Gauss that he recommended her for an honorary doctorate degree from the University of Gttingen. She died before the degree could be awarded. Additional reading Louis L. Bucciarelli and Nancy Dworsky, Sophie Germain: An Essay in the History of the Theory of Elasticity (1980).