26 juni 2019 - Sofya Kovalevskaya (Text by David Hokken) Last month, we saw that Florence Nightingale supported the allied forces in the Crimean War (1853-1856) as a statistician and nurse. She was not the only great female mathematician affected by this war. On the other side of the battlefield fought General Korvin-Krukovsky. The general had to retire from the army after Russia’s defeat, and he and his family, including the young Sofya Kovalevskaya (1850-1891), moved from Moscow’s busy city life to their house in the countryside in Palibino. Here, Sofya and her sister spent their days enjoying the forests and lakes that surrounded the house; but the mysterious symbols on the lecture notes that covered the walls of the children’s room, could grab Sofya’s attention for hours straight. Almost a decade later, when she got lessons from the Petersburg professor Strannolyubsky in differential calculus, Sofya suddenly remembered the lecture notes in the room (which had been put there due to a shortage of wallpaper); the concept of limit, as she wrote in her memoir, then appeared to her as an old friend. Strannolyubsky was a well-known champion of women’s right to education. He surely helped Kovalevskaya to determine her priorities in life. Strannolyubsky introduced her to the Russian nihilists, who held firm beliefs in the power of education and the equality of man and woman and who were slowly gaining influence after the war. Nevertheless, Russian universities didn’t allow women to enrol. Without permission from her father, Kovalevskaya was forced to enter into a `fictitious’ marriage to be able to leave the country and seek for higher education elsewhere. In 1869, she and her husband Vladimir Kovalevsky – a young paleontologist, much in love with his wife but emotionally unstable – left for Western Europe. Once in Berlin a year later, the University refused to admit Kovalevskaya on grounds of her sex. However, the famous analyst Weierstrass – who had seldom seen such a ‘gift of intuitive genius’ – offered to tutor her privately. This marked the beginning of a lifelong friendship and fruitful collaboration. Over the course of the next few years, Kovalevskaya worked on a few papers that earned her a doctorate in mathematics in 1874, summa cum laude, from the University of Göttingen. She was the first woman since the Renaissance to do so. One important contribution dating from this time was her proof of the Cauchy-Kovalevskaya theorem in the area of partial differential equations. After a few years back in Russia that ended in a financial disaster for the Kovalevsky’s (eventually leading to Vladimir’s suicide), Kovalevskaya got an unpaid position as Privatdozent at the University College of Stockholm in 1883. In June 1884, she received the professorship at that university and entered the editorial board of Acta Mathematica both as the first woman in any field. Her research now included topics in mechanics and mathematical physics. In 1888, she won the Prix Bordin for three papers that she wrote on the revolution of a solid body about a fixed point. The jury even raised the prize money from 3,000 to 5,000 francs to honour Kovalevskaya’s remarkable achievements. These papers were so important, because they concluded a century of research carried out by mathematicians such as Euler, Lagrange, Poisson and Jacobi. In them, Kovalevskaya introduced techniques so general that they are still in use today. Sofya Kovalevskaya had a great influence on the position of women in both Europe and Russia. Without her and her female friends – who were the first to receive doctorates in medicine, the sciences, and law – it would probably have taken many more years for universities to open their doors for women. In terms of mathematics, Kovalevskaya’s ideas and style were admired for their novelty and freshness; she was the most successful female scientist of her generation. In addition, she wrote two well-received books on her life. Sofya Kovalevskaya died in Stockholm at the age of forty-one, leaving behind a small but significant scientific legacy. Bibliography Roger Cooke. The Mathematics of Sonya Kovalevskaya. Springer Science & Business Media, 2012.Ann Hibner Koblitz. A convergence of lives: Sofia Kovalevskaia, scientist, writer, revolutionary. Rutgers University Press, 1993. Ann Hibner Koblitz. “Science, women, and the Russian intelligentsia: the generation of the 1860s”. In: Isis 79.2 (1988), pp. 208–226. Beatrice Stillman and Sofya Kovalevskaya. A Russian Childhood. Springer Verlag, 1978.