Leopoldo Nachbin (7 January 1922 – 3 April 1993) was a Brazilian

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, mathematical structure, structure, space, Mathematica ...

of Jewish origins who dealt with

topology Topology (from the Greek language, Greek words , and ) is the branch of mathematics concerned with the properties of a Mathematical object, geometric object that are preserved under Continuous function, continuous Deformation theory, deformat ...

and

harmonic analysis Harmonic analysis is a branch of mathematics concerned with investigating the connections between a function and its representation in frequency. The frequency representation is found by using the Fourier transform for functions on unbounded do ...

. Nachbin was born in

Recife Recife ( , ) is the Federative units of Brazil, state capital of Pernambuco, Brazil, on the northeastern Atlantic Ocean, Atlantic coast of South America. It is the largest urban area within both the North Region, Brazil, North and the Northeast R ...

, and is best known for

Nachbin's theorem In mathematics, in the area of complex analysis, Nachbin's theorem (named after Leopoldo Nachbin) is a result used to establish bounds on the growth rates for analytic functions. In particular, Nachbin's theorem may be used to give the domain o ...

. He died, aged 71, in

Rio de Janeiro Rio de Janeiro, or simply Rio, is the capital of the Rio de Janeiro (state), state of Rio de Janeiro. It is the List of cities in Brazil by population, second-most-populous city in Brazil (after São Paulo) and the Largest cities in the America ...

. He went to primary school in Recife with Brazilian literary giant

Clarice Lispector Clarice Lispector (, born Chaya Pinkhasivna Lispector (; ) December 10, 1920December 9, 1977) was a Ukrainian-born Brazilian novelist and short story writer. Her distinctive and innovative works delve into diverse narrative forms, weaving them ...

. He is featured in one of her short stories, called “As Grandes Punições” (The Great Punishments) in her book “Aprendendo a Viver,” by the Rocco publishing house. Nachbin was a Ph.D. student of

Laurent Schwartz Laurent-Moïse Schwartz (; 5 March 1915 – 4 July 2002) was a French mathematician. He pioneered the theory of Distribution (mathematics), distributions, which gives a well-defined meaning to objects such as the Dirac delta function. He was awar ...

at the

University of Chicago The University of Chicago (UChicago, Chicago, or UChi) is a Private university, private research university in Chicago, Illinois, United States. Its main campus is in the Hyde Park, Chicago, Hyde Park neighborhood on Chicago's South Side, Chic ...

. His Ph.D. students include

Francisco Antônio Dória Francisco is the Spanish and Portuguese form of the masculine given name ''Franciscus''. Meaning of the name Francisco In Spanish, people with the name Francisco are sometimes nicknamed "Paco (name), Paco". Francis of Assisi, San Francisco de A ...

and

Seán Dineen Seán Dineen (12 February 1944 – 18 January 2024) was an Irish mathematician specialising in complex analysis. His academic career was spent, in the main, at University College Dublin (UCD) where he was Professor of Mathematics, serving as Head ...

. His monographs ''Topology and Order'' and ''The Haar Integral'', both published by Van Nostrand-Reinhold in 1965, are regarded as exceptional expositions of the subjects. Overall he authored ten books, most of which were published internationally, and edited a dozen tomes of the prestigiou
''North-Holland Mathematical Studies''
series between 1970 and the early 1980s. He is best known for a Tauberian-type theorem (

) on the growth rate of

analytic function In mathematics, an analytic function is a function that is locally given by a convergent power series. There exist both real analytic functions and complex analytic functions. Functions of each type are infinitely differentiable, but complex ...

s, and for the so-called Hewitt–Nachbin space, a topological linear space that is bornological in the

compact-open topology In mathematics, the compact-open topology is a topology defined on the set of continuous maps between two topological spaces. The compact-open topology is one of the commonly used topologies on function spaces, and is applied in homotopy theory ...

. He was an

invited speaker at the International Congress of Mathematicians An invitation system is a method of encouraging people to join an organization, such as a Club (organization), club or a website. In regular society, it refers to any system whereby new members are chosen; they cannot simply apply. In relation to w ...

(ICM) of 1962 in Stockholm ("Résultats récents et problèmes de nature algébrique en théorie de l'approximation"), being the first Brazilian speaker at the ICM.International Mathematical Union (IMU)
"ICM Plenary and Invited Speakers since 1897"
. ''mathunion.org''. Retrieved on 8 July 2017.

Bibliography

*''Topology and Order'' (Van Nostrand-Reinhold, 1965) *''The Haar Integral'' (Van Nostrand-Reinhold, 1965; Krieger 1976) *''Elements of Approximation Theory'' (Van Nostrand-Reinhold, 1967; Krieger 1976) *''Introdução à Álgebra'' (McGraw-Hill, 1971, in Portuguese)

References

* J. Horváth. ttps://books.google.com/books?id=cAIMuQAACAAJ The life and works of Leopoldo Nachbin

External links

*
Leopoldo Nachbin, 1922-1993

Os trabalhos de Leopoldo Nachbin (1922-1993), by Jorge Mujica, in Portuguese, free translation: "The Works of Leopoldo Nachbin (1922-1993)"
20th-century Brazilian mathematicians 1922 births 1993 deaths Brazilian Jews Topologists Instituto Nacional de Matemática Pura e Aplicada researchers Mathematical analysts {{Mathematician-stub