Sofya Vasilyevna Kovalevskaya, (born January 15, 1850, Moscow, Russia—died February 10, 1891, Stockholm, Sweden), mathematician and writer who made a valuable contribution to the theory of partial differential equations. She was the first woman in modern Europe to gain a doctorate in mathematics, the first to join the editorial board of a scientific journal, and the first to be appointed professor of mathematics.In 1868 Kovalevskaya entered into a marriage of convenience with a young paleontologist, Vladimir Kovalevsky, in order to leave Russia and continue her studies. The pair traveled together to Austria and then to Germany, where in 1869 she studied at the University of Heidelberg under the mathematicians Leo Königsberger and Paul du Bois-Reymond and the physicist Hermann von Helmholtz. The following year she moved to Berlin, where, having been refused admission to the university on account of her gender, she studied privately with the mathematician Karl Weierstrass. In 1874 she presented three papers—on partial differential equations, on Saturn’s rings, and on elliptic integrals—to the University of Göttingen as her doctoral dissertation and was awarded the degree, summa cum laude, in absentia. Her paper on partial differential equations, the most important of the three papers, won her valuable recognition within the European mathematical community. It contains what is now commonly known as the Cauchy-Kovalevskaya theorem, which gives conditions for the existence of solutions to a certain class of partial differential equations. Having gained her degree, she returned to Russia, where her daughter was born in 1878. She separated permanently from her husband in 1881.
In 1883 Kovalevskaya accepted Magnus Mittag-Leffler’s invitation to become a lecturer in mathematics at the University of Stockholm. She was promoted to full professor in 1889. In 1884 she joined the editorial board of the mathematical journal Acta Mathematica, and in 1888 she became the first woman to be elected a corresponding member of the Russian Academy of Sciences. In 1888 she was awarded the Prix Bordin of the French Academy of Sciences for a paper on the rotation of a solid body around a fixed point.
Kovalevskaya also gained a reputation as a writer, an advocate of women’s rights, and a champion of radical political causes. She composed novels, plays, and essays, including the autobiographical Memories of Childhood (1890) and The Nihilist Woman (1892), a depiction of her life in Russia.