Sophie Germain
1776–1831, Paris, France, Paris, France
Self-taught French mathematician whose work was the most important advance on Fermat's Last Theorem from Euler's 1738 work until Kummer's contributions in the 1840s, and who won the Paris Academy's prize for her pioneering theory of the elasticity of vibrating plates.
Germain was born into a prosperous Paris merchant family and taught herself mathematics from her father's library during the chaos of the French Revolution, reading Newton and Euler by candlelight at night. Barred as a woman from attending the École Polytechnique when it opened in 1794, she obtained lecture notes and submitted work under the pseudonym 'M LeBlanc', drawing the attention and later the mentorship of Joseph-Louis Lagrange. Using the same pseudonym she began an important correspondence with Carl Friedrich Gauss on number theory in 1804, revealing her true identity to him only in 1807.
Germain worked for over a decade on the mathematical theory of elasticity, entering the Paris Academy's competition on vibrating plates three times and finally winning the prize in 1816, the first woman to do so. In number theory she developed what is now called Sophie Germain's theorem, proving a general criterion that ruled out many possible solutions to Fermat's equation for prime exponents, work that remained the deepest advance on Fermat's Last Theorem until the 1840s. She died in Paris in 1831, having never held an academic post; her death certificate listed her occupation only as 'rentière'.
France