Nessim Sibony (20 October 1947 – 30 October 2021) was a French mathematician, specializing in the theory of

several complex variables The theory of functions of several complex variables is the branch of mathematics dealing with functions defined on the complex coordinate space \mathbb C^n, that is, -tuples of complex numbers. The name of the field dealing with the properties ...

and

complex dynamics Complex dynamics, or holomorphic dynamics, is the study of dynamical systems obtained by Iterated function, iterating a complex analytic mapping. This article focuses on the case of algebraic dynamics, where a polynomial or rational function is it ...

in higher dimension. Since 1981, he was professor at the

University of Paris-Sud Paris-Sud University (), also known as the University of Paris — XI (or as the Orsay Faculty of Sciences, University of Paris before 1971), was a French research university distributed among several campuses in the southern suburbs of Paris, ...

Orsay Orsay () is a Communes of France, commune in the Essonne Departments of France, department in Île-de-France in northern France. It is located in the southwestern suburbs of Paris, France, from the Kilometre Zero, centre of Paris. A fortifie ...

Biography

Sibony received in 1974 his PhD from the University of Paris-Sud with thesis ''Problèmes de prolongement analytique et d'approximation polynômiale pondérée''. His research deals with complex analysis and complex dynamics in several variables, including collaboration with

John Erik Fornæss John Erik Fornæss (born 14 October 1946, Hamar, Norway) is a Norwegian-American mathematician. Fornæss received his master's degree in 1970 from the University of Oslo with thesis ''Uniform approximation on manifolds'' and his PhD in 1974 from t ...

and Dinh Tien-Cuong on Fatou-Julia theory in several complex variables and on singular

foliation In mathematics (differential geometry), a foliation is an equivalence relation on an topological manifold, ''n''-manifold, the equivalence classes being connected, injective function, injectively immersed submanifolds, all of the same dimension ...

s by

Riemann surface In mathematics, particularly in complex analysis, a Riemann surface is a connected one-dimensional complex manifold. These surfaces were first studied by and are named after Bernhard Riemann. Riemann surfaces can be thought of as deformed vers ...

s. Independently of

Adrien Douady Adrien Douady (; 25 September 1935 – 2 November 2006) was a French mathematician born in La Tronche, Isère. He was the son of Daniel Douady and Guilhen Douady. Douady was a student of Henri Cartan at the École normale supérieure, and initi ...

and John H. Hubbard, Sibony proved in the 1980s that the

Mandelbrot set The Mandelbrot set () is a two-dimensional set (mathematics), set that is defined in the complex plane as the complex numbers c for which the function f_c(z)=z^2+c does not Stability theory, diverge to infinity when Iteration, iterated starting ...

is connected. In 1985 he received the Vaillant Prize and in 2009 the

Sophie Germain Prize The Sophie Germain Prize (in French: ''Prix Sophie Germain'') is an annual mathematics prize awarded by the French Academy of Sciences to researchers who have carried out fundamental research in mathematics. The award has been conferred every year ...

from the

French Academy of Sciences The French Academy of Sciences (, ) is a learned society, founded in 1666 by Louis XIV at the suggestion of Jean-Baptiste Colbert, to encourage and protect the spirit of French Scientific method, scientific research. It was at the forefron ...

. For 2017 he received the

Stefan Bergman Prize The Stefan Bergman Prize is a mathematics award, funded by the estate of the widow of mathematician Stefan Bergman and supported by the American Mathematical Society. The award is granted for mathematical research in: "1) the theory of the kernel ...

. In 1990 he was an Invited Speaker with talk ''Some recent results on weakly pseudoconvex domains'' at the ICM in

Kyōto Kyoto ( or ; Japanese: , ''Kyōto'' ), officially , is the capital city of Kyoto Prefecture in the Kansai region of Japan's largest and most populous island of Honshu. , the city had a population of 1.46 million, making it the ninth-most pop ...

. He was a senior member of the

Institut Universitaire de France The Institut Universitaire de France (IUF, Academic Institute of France), is a service of the French Ministry of Higher Education that annually distinguishes a small number of university professors for their research excellence, as evidenced by t ...

from 2009 to 2014.

Selected publications

* * *with Dierk Schleicher, Eric Bedford, Tien-Cuong Dinh, Marco Brunella, Marco Abat
''Holomorphic dynamical systems''
Lectures at CIME (Cetraro 2008, in Sibony, Dinh ''Dynamics in several complex variables: Endomorphisms of projective spaces and polynomial like mappings''), Springer Verlag, Lecturenotes in Mathematics, vol. 1998, 2010. *with Tien-Cuong Dinh ''Super-potentials of positive closed currents, intersection theory and dynamics''. Acta Math. 203 (2009), no. 1, 1–82. *with Tien-Cuong Dinh ''Distribution des valeurs de transformations méromorphes et applications''. (French) istribution of the values of meromorphic transformations and applications Comment. Math. Helv. 81 (2006), no. 1, 221–258. *with Tien-Cuong Dinh ''Dynamique des applications d'allure polynomiale''. (French) ynamics of polynomial-like mappingsJ. Math. Pures Appl. (9) 82 (2003), no. 4, 367–423. *with Dominique Cerveau, Étienne Ghys, Jean-Christophe Yocco
''Complex Dynamics and Geometry''
SMF/AMS Texts and Monographs vol. 10, 2003 (in von Sibony: Dynamics of rational maps on

P^k

), French edition SMF 1999 (Panoramas et Synthèses, vol. 8). *with Julien Duval ''Polynomial convexity, rational convexity and currents'', Duke Mathematical Journal, 79 (1995), no. 2, 487–513.
Quelques problemes de prolongement de courants en analyse complexe
Duke Mathematical Journal, 52 (1985), pp. 157–197.

References

External links

Sibony's homepage at U. of Paris-Sud
{{DEFAULTSORT:Sibony, Nessim 20th-century French mathematicians 21st-century French mathematicians Academic staff of Paris-Sud University Living people 1947 births