Jessie MacWilliams
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Florence Jessie Collinson MacWilliams (4 January 1917 – 27 May 1990) was an English
mathematician A mathematician is someone who uses an extensive knowledge of mathematics in their work, typically to solve mathematical problems. Mathematicians are concerned with numbers, data, quantity, structure, space, models, and change. History On ...
who contributed to the field of
coding theory Coding theory is the study of the properties of codes and their respective fitness for specific applications. Codes are used for data compression, cryptography, error detection and correction, data transmission and data storage. Codes are stud ...
, and was one of the first women to publish in the field. MacWilliams' thesis "Combinatorial Problems of Elementary Group Theory" (or "Combinatorial Problems of Elementary Abelian Groups") contains one of the most important combinatorial results in coding theory, and is now known as the
MacWilliams Identity In coding theory, the weight enumerator polynomial of a binary linear code specifies the number of words of each possible Hamming weight. Let C \subset \mathbb_2^n be a binary linear code length n. The weight distribution is the sequence of numb ...
.


Education and career

MacWilliams was born in Stoke-on-Trent, England and studied at the
University of Cambridge , mottoeng = Literal: From here, light and sacred draughts. Non literal: From this place, we gain enlightenment and precious knowledge. , established = , other_name = The Chancellor, Masters and Schola ...
, receiving her BA in 1938 and her MA in the following year."F. Jessie MacWilliams", Biographies of Women Mathematicians
Agnes Scott College, retrieved 2013-04-05.
She moved to the United States in 1939 and studied at
Johns Hopkins University Johns Hopkins University (Johns Hopkins, Hopkins, or JHU) is a private university, private research university in Baltimore, Maryland. Founded in 1876, Johns Hopkins is the oldest research university in the United States and in the western hem ...
. One year later she left Johns Hopkins for
Harvard University Harvard University is a private Ivy League research university in Cambridge, Massachusetts. Founded in 1636 as Harvard College and named for its first benefactor, the Puritan clergyman John Harvard, it is the oldest institution of higher le ...
. In 1955 she became a programmer and learned coding theory at
Bell Labs Nokia Bell Labs, originally named Bell Telephone Laboratories (1925–1984), then AT&T Bell Laboratories (1984–1996) and Bell Labs Innovations (1996–2007), is an American industrial Research and development, research and scientific developm ...
where she spent most of her career. Although she did major research at Bell Labs, she was denied a promotion to a mathematics research position until she received a Ph.D. She would proceed to fulfill some of the PhD's requirements while working at Bell Labs and taking care of her family, but she completed her PhD after returning to Harvard for one more year (1961–1962), under the supervision of
Andrew Gleason Andrew Mattei Gleason (19212008) was an American mathematician who made fundamental contributions to widely varied areas of mathematics, including the solution of Hilbert's fifth problem, and was a leader in reform and innovation in teaching at ...
. MacWilliams worked with Gleason to produce her thesis entitled "Combinatorial Problems of Elementary Group Theory". Both MacWilliams and her daughter Anne, who later obtained a PhD in Mathematics, were studying mathematics at Harvard that year.


Contributions

Her formula is known as the
MacWilliams identity In coding theory, the weight enumerator polynomial of a binary linear code specifies the number of words of each possible Hamming weight. Let C \subset \mathbb_2^n be a binary linear code length n. The weight distribution is the sequence of numb ...
, and is how MacWilliams is known. MacWilliams' result was later critical in proving an important bound on code rate, called the 'linear programming bound'. From 1962 to 1976, Macwilliams produced important results on algebraic constructions and combinatorial properties of codes. She worked on
cyclic code In coding theory, a cyclic code is a block code, where the circular shifts of each codeword gives another word that belongs to the code. They are error-correcting codes that have algebraic properties that are convenient for efficient error detecti ...
s, generalizing them to Abelian group codes. With H.B. Mann, MacWilliams gave a solution to a difficult problem involving certain design matrices, which they published in their paper titled "On the ''p''-rank of the design matrix of a difference set". One of MacWilliams' significant achievements was her encyclopedic book, ''The Theory of Error-Correcting Codes'', which she wrote in collaboration with
Neil Sloane __NOTOC__ Neil James Alexander Sloane (born October 10, 1939) is a British-American mathematician. His major contributions are in the fields of combinatorics, error-correcting codes, and sphere packing. Sloane is best known for being the creator a ...
and was published in 1977. The book is stated as being "Perhaps the most comprehensive text on the algebraic and combinatorial properties of error-correcting codes, and of abiding interest to both mathematicians and engineers. It was one of the major works responsible for laying the foundation for a revolution in communication technology that is being played out even today".


Recognition

In 1980 she was the first
Noether Lecturer The Noether Lecture is a distinguished lecture series that honors women "who have made fundamental and sustained contributions to the mathematical sciences". The Association for Women in Mathematics (AWM) established the annual lectures in 1980 as t ...
.


References


Further reading

* {{DEFAULTSORT:Macwilliams, Jessie 1917 births 1990 deaths 20th-century English mathematicians Johns Hopkins University alumni Harvard University alumni People from Stoke-on-Trent Alumni of the University of Cambridge Scientists at Bell Labs 20th-century women mathematicians