Theodore Joseph Rivlin (11 September 1926, Brooklyn – 22 July 2006,

Croton-on-Hudson Croton-on-Hudson ( ) is a village in Westchester County, New York, United States. The population was 8,327 at the 2020 United States census over 8,070 at the 2010 census. It is located in the town of Cortlandt as part of New York City's northern ...

) was an American mathematician, specializing in

approximation theory In mathematics, approximation theory is concerned with how function (mathematics), functions can best be approximation, approximated with simpler functions, and with quantitative property, quantitatively characterization (mathematics), characteri ...

. He is known for his 1969 book ''An Introduction to the Approximation of Functions'' (Dover reprint, 1981), which became a standard text.

Education and career

Rivlin received in 1948 his bachelor's degree from

Brooklyn College Brooklyn College is a public university in Brooklyn in New York City, United States. It is part of the City University of New York system and enrolls nearly 14,000 students on a campus in the Midwood and Flatbush sections of Brooklyn as of fall ...

. After serving in the

United States Army Air Force The United States Army Air Forces (USAAF or AAF) was the major land-based aerial warfare service component of the United States Army and ''de facto'' aerial warfare service branch of the United States during and immediately after World War II ...

for eighteen months, he became a graduate student in mathematics at

Harvard University Harvard University is a Private university, private Ivy League research university in Cambridge, Massachusetts, United States. Founded in 1636 and named for its first benefactor, the History of the Puritans in North America, Puritan clergyma ...

, where he received in 1953 his Ph.D. with thesis advisor

Joseph L. Walsh __NOTOC__ Joseph Leonard Walsh (September 21, 1895 – December 6, 1973) was an American mathematician who worked mainly in the field of analysis. The Walsh function and the Walsh–Hadamard code are named after him. The Grace–Walsh–Szeg� ...

and thesis ''Overconvergent

Taylor series In mathematics, the Taylor series or Taylor expansion of a function is an infinite sum of terms that are expressed in terms of the function's derivatives at a single point. For most common functions, the function and the sum of its Taylor ser ...

and the zeroes of related polynomials''. Rivlin from 1952 to 1955 taught mathematics at

Johns Hopkins University The Johns Hopkins University (often abbreviated as Johns Hopkins, Hopkins, or JHU) is a private university, private research university in Baltimore, Maryland, United States. Founded in 1876 based on the European research institution model, J ...

and from 1955 to 1956 was a research associate at the Institute for Mathematics Sciences at New York University (later renamed the

Courant Institute of Mathematical Sciences The Courant Institute of Mathematical Sciences (commonly known as Courant or CIMS) is the mathematics research school of New York University (NYU). Founded in 1935, it is named after Richard Courant, one of the founders of the Courant Institute ...

). He was from 1956 to 1959 a senior mathematical analyst at the Fairchild Engine and Airplane Corporation in Deer Park on

Long Island Long Island is a densely populated continental island in southeastern New York (state), New York state, extending into the Atlantic Ocean. It constitutes a significant share of the New York metropolitan area in both population and land are ...

; there he began intensive study of approximation theory and

Chebyshev polynomial The Chebyshev polynomials are two sequences of orthogonal polynomials related to the trigonometric functions, cosine and sine functions, notated as T_n(x) and U_n(x). They can be defined in several equivalent ways, one of which starts with tr ...

s in connection with his work on developing thermodynamic tables. From 1959 until his retirement nearly 35 years later, Rivlin was a research staff member at

IBM International Business Machines Corporation (using the trademark IBM), nicknamed Big Blue, is an American Multinational corporation, multinational technology company headquartered in Armonk, New York, and present in over 175 countries. It is ...

Thomas J. Watson Research Center The Thomas J. Watson Research Center is the headquarters for IBM Research. Its main laboratory is in Yorktown Heights, New York, 38 miles (61 km) north of New York City. It also operates facilities in Cambridge, Massachusetts and Albany, ...

Yorktown Heights, New York Yorktown Heights is a census-designated place (CDP) in the town of Yorktown in Westchester County, New York, United States. The population was 1,781 at the 2010 census. History Yorktown Heights is in the town of Yorktown, New York, in northe ...

. He was on sabbatical from 1969 to 1970 at

Stanford University Leland Stanford Junior University, commonly referred to as Stanford University, is a Private university, private research university in Stanford, California, United States. It was founded in 1885 by railroad magnate Leland Stanford (the eighth ...

's Computer Science Department and from 1976 to 1977 at

Imperial College London Imperial College London, also known as Imperial, is a Public university, public research university in London, England. Its history began with Prince Albert of Saxe-Coburg and Gotha, Prince Albert, husband of Queen Victoria, who envisioned a Al ...

's Mathematics Department. From 1966 to 1976 Rivlin was an adjunct professor of mathematics at the Graduate Center of the

City University of New York The City University of New York (CUNY, pronounced , ) is the Public university, public university system of Education in New York City, New York City. It is the largest urban university system in the United States, comprising 25 campuses: eleven ...

, where he lectured on approximation theory. For many years he was an associate editor for the ''

Journal of Approximation Theory The ''Journal of Approximation Theory'' is "devoted to advances in pure and applied approximation theory and related areas." References External links ''Journal of Approximation Theory'' web site''Journal of Approximation Theory'' home page a ...

'' and wrote over 80 research articles on approximation theory and computational mathematics. ''The Annals of Numerical Analysis'' published in 1997 a special issue entitled ''The Heritage of P.L. Chebyshev: A Festschrift in honor of the 70th birthday of T.J. Rivlin''.

Selected publications

Articles

* with Nesmith C. Ankeny: * with Harold S. Shapiro: * with Richard Kelisky: * with Charles A. Micchelli and

Shmuel Winograd __NOTOC__ Shmuel Winograd (; January 4, 1936 – March 25, 2019) was an Israeli-American computer scientist, noted for his contributions to computational complexity. He has proved several major results regarding the computational aspects of arit ...

: * with C. A. Micchelli: * with C. A. Micchelli:

Books

*; * **

References

{{DEFAULTSORT:Rivlin, Theodore J. 1926 births 2006 deaths 20th-century American mathematicians Approximation theorists American mathematical analysts Brooklyn College alumni Harvard University alumni IBM employees