__NOTOC__ Joseph Leonard Walsh (September 21, 1895 – December 6, 1973) was an American mathematician who worked mainly in the field of

analysis Analysis ( : analyses) is the process of breaking a complex topic or substance into smaller parts in order to gain a better understanding of it. The technique has been applied in the study of mathematics and logic since before Aristotle (3 ...

. The

Walsh function In mathematics, more specifically in harmonic analysis, Walsh functions form a complete orthogonal set of functions that can be used to represent any discrete function—just like trigonometric functions can be used to represent any continuous ...

and the

Walsh–Hadamard code The Hadamard code is an error-correcting code named after Jacques Hadamard that is used for error detection and correction when transmitting messages over very noisy or unreliable channels. In 1971, the code was used to transmit photos of Mar ...

are named after him. The Grace–Walsh–Szegő coincidence theorem is important in the study of the location of the zeros of multivariate polynomials. He became a member of the National Academy of Sciences in 1936 and served 1949–51 as president of the

American Mathematical Society The American Mathematical Society (AMS) is an association of professional mathematicians dedicated to the interests of mathematical research and scholarship, and serves the national and international community through its publications, meetings, ...

. Altogether he published 279 articles (research and others) and seven books, and advised 31 PhD students. For most of his professional career he studied and worked at

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 high ...

. He received a B.S. in 1916 and a PhD in 1920. The Advisor of his PhD was

Maxime Bôcher Maxime Bôcher (August 28, 1867 – September 12, 1918) was an American mathematician who published about 100 papers on differential equations, series, and algebra. He also wrote elementary texts such as ''Trigonometry'' and ''Analytic Geometry''. ...

. Walsh started to work as lecturer in Harvard afterwards and became a full professor in 1935. He was an Invited Speaker of the ICM in 1920 at Strasbourg. With two different scholarships he was able to study in Paris under

Paul Montel Paul Antoine Aristide Montel (29 April 1876 – 22 January 1975) was a French mathematician. He was born in Nice, France and died in Paris, France. He researched mostly on holomorphic functions in complex analysis. Montel was a student of Émile ...

(1920–21) and in Munich under

Constantin Carathéodory Constantin Carathéodory ( el, Κωνσταντίνος Καραθεοδωρή, Konstantinos Karatheodori; 13 September 1873 – 2 February 1950) was a Greek mathematician who spent most of his professional career in Germany. He made significant ...

(1925–26). From 1937 to 1942 he served as chairman of his department at Harvard. During

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing ...

he served as an officer in the US navy and was promoted to captain right after end of the war. After his retirement from Harvard in 1966 he accepted a position at the

University of Maryland The University of Maryland, College Park (University of Maryland, UMD, or simply Maryland) is a public land-grant research university in College Park, Maryland. Founded in 1856, UMD is the flagship institution of the University System of M ...

where he continued to work up to a few months before his death.

Works

Articles

* * * with

Wladimir Seidel Wladimir P. Seidel (December 21, 1907 – January 12, 1981) was a Russian-born German-American mathematician, and Doctor of Mathematics. He held a fellowship as a Benjamin Peirce Professor in Harvard University. During World War II, he was wi ...

: * with T. S. Motzkin: * with J. P. Evans: * with Lawrence Rosenfeld: * * with J. H. Ahlberg & E. N. Nilson: * with J. H. Ahlberg & E. N. Nilson: * with J. H. Ahlberg & E. N. Nilson:

Books

''Interpolation and approximation by rational functions in the complex domain''
AMS Colloquium Publications 1935, 5th edn. 1969
''The location of critical points of analytic and harmonic functions''
AMS Colloquium Publications, vol. 34, 1950 * with John Harold Ahlberg, Edwin Norman Nilson: ''The theory of splines and their applications'', Academic Press 1967,

References

Additional sources

* * * Morris Marden:
''Joseph L. Walsh in Memoriam''
Bulletin of the American Mathematical Society, Volume 81, issue 1, January 1975 * {{DEFAULTSORT:Walsh, Joseph Leonard 1895 births 1973 deaths 20th-century American mathematicians Harvard University alumni Harvard University faculty Members of the United States National Academy of Sciences Presidents of the American Mathematical Society Mathematicians from Washington, D.C.