KOVALEVSKY, SONYA [SOPHIE] Rus sian mathematician, was born at Moscow on Jan. 15, 1850. She married in 1868 a young student, Waldemar Kovalevsky, and the two went together to Germany to continue their studies. In 1869 she went to Heidelberg where she studied under H. von Helmholtz, G. R. Kirchhoff, L. Konigsberger and P. du Bois Reymond, and from 1871-1874 read privately with Karl Weier strass at Berlin, as the public lectures were not then open to women. In 1874 the University of Gottingen granted her a degree in absentia, excusing her from the oral examination in considera tion of the three dissertations sent in, one of which, on the theory of partial differential equations, is one of her most remarkable works. After lecturing in Stockholm university, Madame Kovalev sky was appointed professor there in 1884, at the instance of Gus tav Mittag-Leffler, also a pupil of Weierstrass, and held the post until her death. In 1888 she achieved the greatest of her suc cesses, gaining the Prix Bordin offered by the Paris academy. The problem set was "to perfect in one important point the theory of a movement of a solid body round an immovable point," and her solution added a result of the highest interest to those submitted to us by Leonhard Euler and J. L. Lagrange. So
remarkable was this work that the value of the prize was doubled as a recognition of unusual merit. Unfortunately Madame Koval evsky did not live to reap the full reward of her labours, for she died on February 1o, 1891, just as she had attained the height of her fame and had won recognition, even in her own country, by election to membership of the St. Petersburg Academy of Science.
See Anna Leffler, Sonja Kovalevsky (1892), based on Sonya's auto biography, which is a human document of extraordinary interest.