#### by Emmy E. Pierce and Linda Kirby

Mary Lucy Cartwright was born on December 17, 1900. Her father was the vicar of Aynho, Northamptonshire. She was educated at home in Aynho until the age of 11, when she was sent to Leamington High School. It was later, in her last year at the Godolphin School in Salisbury, that Cartwright was encouraged to study mathematics.

In 1919, Cartwright became one of five women studying mathematics at Oxford University. She suffered a disappointment in her second-year Mathematical Moderations, when she received second-class honors instead of the first-class award for which she had been aiming. For a time Cartwright seriously considered giving up mathematics altogether and returning to history, which had been her first love and her best subject as a child. Ultimately, however, she decided to stay in the discipline, and in 1923 she graduated from Oxford with a first-class degree from her Final Honors. It was the second year in which Oxford allowed women allowed to take Final Degrees.

Cartwright taught mathematics in Worcester and Buckinghamshire for the
next four years before returning to Oxford for her D.Phil. in 1928.
Her studies were supervised by
G. H. Hardy,
whose evening sessions she had attended as an undergraduate, and
E. C. Titchmarsh.
In 1930 she was awarded her D.Phil and her thesis, “The zeros of integral
functions of special types,” was published in two parts in the
*Quarterly Journal of Mathematics*, vol. 1 (1930) and vol. 2 (1931).

The end of Cartwright’s education at Oxford began a transition to many years of research and teaching. After finishing her doctoral thesis, Cartwright was awarded a research fellowship at Girton College, Cambridge University, to continue her study of the theory of functions. By 1935, she had been appointed a Lecturer in Mathematics at Cambridge. She would hold this post until 1959, when she would become a Reader in the Theory of Functions, the position she would retain until her retirement. During this time she also served as Director of Studies in Mathematics, and as Mistress of Girton College from 1949 to 1989. Although she took on fairly few research students (in an effort to avoid becoming overburdened with both administrative and teaching duties), she was known as an excellent and meticulous supervisor of those students she did accept.

During her career, Cartwright published over 100 papers in classical analysis, differential equations, and related topological problems. She made ground-breaking contributions to chaos theory, after becoming intrigued by a memorandum put out by the Radio Research Board of the Department of Scientific and Industrial Research. The Board intended “to bring to the notice of mathematicians certain types of non-linear differential equations involved in the technique of radio engineering.” As a result of this memorandum, Cartwright collaborated for many years with John E. Littlewood (who had first met Cartwright when he examined her doctoral thesis) on the solutions to the Van der Pol equation. Besides the academic value of the team’s discoveries, the work also enabled significant practical improvements to the radio amplifiers used for communication during World War II.

Cartwright retired from Girton in 1969, but continued to teach as a visiting professor in England, America and Poland. By this time she had been elected a Fellow of the Royal Society (the first woman mathematician to be so honored, and the only woman mathematician until 1995); received honorary doctorates from the Universities of Edinburgh, Leeds, Hull, Wales, and Oxford; and been awarded both the Sylvester Medal of the Royal Society and the de Morgan medal by the London Mathematical Society (where she had served as president from 1961 to 1963). She was appointed Dame of the British Empire the year after she left Girton College.

After years of teaching abroad, Cartwright returned to Cambridge, where she was one of the editors of The Collected Papers of G. H. Hardy. She died there in 1998.