Gaston Maurice Julia (3 February 1893 – 19 March 1978) was a French Algerian mathematician who devised the formula for the

Julia set In the context of complex dynamics, a branch of mathematics, the Julia set and the Fatou set are two complementary sets (Julia "laces" and Fatou "dusts") defined from a function. Informally, the Fatou set of the function consists of values wi ...

. His works were popularized by French mathematician Benoit Mandelbrot; the Julia and Mandelbrot fractals are closely related. He founded, independently with Pierre Fatou, the modern theory of holomorphic dynamics.

Military service

Julia was born in the

Algeria ) , image_map = Algeria (centered orthographic projection).svg , map_caption = , image_map2 = , capital = Algiers , coordinates = , largest_city = capital , relig ...

n town of

Sidi Bel Abbes ''Sidi'' or ''Sayidi'', also Sayyidi and Sayeedi, ( ar, سيدي, Sayyīdī, Sīdī (dialectal) "milord") is an Arabic masculine title of respect. ''Sidi'' is used often to mean "saint" or "my master" in Maghrebi Arabic and Egyptian Arabic. W ...

, at the time governed by the French. During his youth, he had an interest in mathematics and music. His studies were interrupted at the age of 21, when France became involved in

World War I World War I (28 July 1914 11 November 1918), often abbreviated as WWI, was one of the deadliest global conflicts in history. Belligerents included much of Europe, the Russian Empire, the United States, and the Ottoman Empire, with fightin ...

and Julia was conscripted to serve with the army. During an attack he suffered a severe injury, losing his nose. His many operations to remedy the situation were all unsuccessful, and for the rest of his life he resigned himself to wearing a leather strap around the area where his nose had been.

Career in mathematics

Julia gained attention for his mathematical work at the age of 25, in 1918, when his 199-page ''Mémoire sur l'itération des fonctions rationnelles'' ("Memoir on the Iteration of Rational Functions") was featured in the '' Journal de Mathématiques Pures et Appliquées''. This article gained immense popularity among mathematicians and earned him the ''Grand Prix des Sciences Mathématiques'' of the French Academy of Sciences in 1918. But after this brief moment of fame, his works were mostly forgotten until the day Benoit Mandelbrot mentioned them in his works on fractals. On 19 March 1978, Julia died in Paris at the age of 85. Julia was also father to

Marc Julia Marc Julia (23 October 1922 – 29 June 2010) was a French chemist and the winner of the 1990 CNRS Gold Medal in chemistry. He discovered the Julia olefination reaction in 1973. Biography Julia was born in 1922 in Paris as son of the renowned m ...

, the French organic chemist who invented the

Julia olefination The Julia olefination (also known as the Julia–Lythgoe olefination) is the chemical reaction used in organic chemistry of phenyl sulfones (1) with aldehydes (or ketones) to give alkenes (olefins)(3) after alcohol functionalization and reductive ...

World War Two and collaboration

Julia had

collaborated Collaboration (from Latin ''com-'' "with" + ''laborare'' "to labor", "to work") is the process of two or more people, entities or organizations working together to complete a task or achieve a goal. Collaboration is similar to cooperation. Most ...

with the

Nazi Germany Nazi Germany (lit. "National Socialist State"), ' (lit. "Nazi State") for short; also ' (lit. "National Socialist Germany") (officially known as the German Reich from 1933 until 1943, and the Greater German Reich from 1943 to 1945) was ...

during the occupation of France. He searched and found French mathematicians to collaborate with the Zentralblatt für Mathematik, and was suspended for a few weeks after the

liberation of France The liberation of France in the Second World War was accomplished through diplomacy, politics and the combined military efforts of the Allied Powers, Free French forces in London and Africa, as well as the French Resistance. Nazi Germany inv ...

. But according to Michèle Audin:

Books

*''Oeuvres'', 6 vols., Paris, Gauthier-Villars 1968-1970 (eds.

Jacques Dixmier Jacques Dixmier (born 24 May 1924) is a French mathematician. He worked on operator algebras, especially C*-algebras, and wrote several of the standard reference books on them, and introduced the Dixmier trace and the Dixmier mapping. Biogra ...

, Michel Hervé, with foreword by Julia) *''Leçons sur les Fonctions Uniformes à Point Singulier Essentiel Isolé'', Gauthier-Villars 1924 (rédigées par P. Flamant) *''Eléments de géométrie infinitésimale'', Gauthier-Villars 1927 *''Cours de Cinématique'', Gauthier-Villars 1928, 2nd edition 1936 *''Exercices d'Analyse'', 4 vols., Gauthier-Villars, 1928 - 1938, 2nd edition 1944, 1950 *''Principes Géométriques d'Analyse'', 2 vols., Gauthier-Villars, 1930, 1932 *''Essai sur le Développement de la Théorie des Fonctions de Variables Complexes'', Gauthier-Villars 1933 *''Introduction Mathématique aux Theories Quantiques'', 2 vols., Gauthier-Villars 1936, 1938, 2nd edition 1949, 1955 *''Eléments d'algèbre'', Gauthier-Villars 1959 *''Cours de Géométrie'', Gauthier-Villars 1941 *''Cours de géométrie infinitésimale'', Gauthier-Villars, 2nd edition 1953 *''Exercices de géométrie'', 2 vols., Gauthier-Villars 1944, 1952 *''Leçons sur la représentation conforme des aires simplement connexes'', Gauthier-Villars 1931, 2nd edition 1950 *''Leçons sur la représentation conforme des aires multiplement connexes'', Gauthier-Villars 1934 *''Traité de Théorie de Fonctions'', Gauthier-Villars 1953 *''Leçons sur les fonctions monogènes uniformes d'une variable complexe'', Gauthier-Villars 1917 *''Étude sur les formes binaires non quadratiques à indéterminées réelles ou complexes, ou à indéterminées conjuguées'', Gauthier-Villars 1917

References

External links

* * * ''Memoir on iteration of rational functions'', English translation in parts
1/72/73/74/75/76/77/7

Downloadable articles at Numdam

Diplomica GmbH Hamburg (2008) * Daniel Alexander, Felice Iavernaro, Alessandro Rosa
''Early days in complex dynamics: a history of complex dynamics in one variable during 1906-1942''
History of Mathematics 38, American Mathematical Society 2012 {{DEFAULTSORT:Julia, Gaston 1893 births 1978 deaths École Normale Supérieure alumni 20th-century French mathematicians University of Paris alumni University of Paris faculty Members of the French Academy of Sciences People from Sidi Bel Abbès French military personnel of World War I Pieds-Noirs Migrants from French Algeria to France