Sofya Kovalevskaya first met calculus on the wallpaper of her childhood bedroom
When the family ran short of wallpaper at their country estate, one child's room was covered with old lecture notes on calculus from her father's student days. Eleven-year-old Sofya Kovalevskaya stared at the strange formulas for hours, and she later went on to become the first woman to earn a modern doctorate in mathematics.
Born in Moscow on 15 January 1850 into a noble family, she soon showed startling ability. A physicist neighbour, Nikolai Tyrtov, noticed she had worked out for herself an approximation of trigonometric functions to follow his textbook, and dubbed her a new Pascal. During the winter of 1866 to 1867 in St. Petersburg she took private calculus lessons from Aleksandr Strannolyubsky, an advocate of university education for women.
Russian universities, however, barred women, and studying abroad required written consent from a father or husband. In 1868 she solved the problem with a marriage of convenience to Vladimir Kovalevsky, a young palaeontologist. In Heidelberg she won permission to audit lectures by Helmholtz, Kirchhoff and Bunsen. In London, aged nineteen, she was drawn into a debate at George Eliot's salon with Herbert Spencer on whether women could think abstractly.
Berlin's university would not let her attend even as a listener, so from 1870 Karl Weierstrass taught her privately, covering his full lecture course over three years. In 1874 Göttingen awarded her a doctorate summa cum laude for three papers, on partial differential equations, the dynamics of Saturn's rings and elliptic integrals. The first contains what is now called the Cauchy–Kovalevskaya theorem, which guarantees that certain such equations have well-behaved local solutions.
Back in Russia there was no academic job for her. The couple dabbled in property and an oil company, lived together as a real married pair from 1875, and had a daughter nicknamed Fufa before Sofya left for good to return to mathematics. In 1883 her fellow Weierstrass student Gösta Mittag-Leffler found her a post at Stockholm University, and she became the first woman in modern Europe to hold a full professorship in mathematics. She died on 10 February 1891.
Source: Sofya Kovalevskaya
