Jean-Pierre Demailly (25 September 1957 – 17 March 2022) was a French mathematician who worked in complex geometry.

He was a professor at Université Grenoble Alpes and a permanent member of the French Academy of Sciences.

[1] He entered the École Normale Supérieure in 1975, where he received his agrégation in 1977 and graduated in 1979.

[2] During this time, he received an undergraduate licence degree from Paris Diderot University in 1976 and a diplôme d'études approfondies under Henri Skoda at the Pierre and Marie Curie University in 1979.

[1] He received his Doctorat d'État in 1982 under the direction of Skoda at the Pierre and Marie Curie University, with thesis "Sur différents aspects de la positivité en analyse complexe".

[2] From June 2003 onwards, he led the Groupe de réflexion interdisciplinaire sur les programmes (GRIP), which ran experimental classes in primary schools.

[2] He also wrote and co-authored several Unix and Linux libraries starting in the 1990s, including xpaint, sunclock, and dmg2img.

Demailly's regularization theorem says, in particular, that any big class can be represented by a Kähler current with analytic singularities.

In particular, Boucksom, Demailly, Păun, and Peternell showed that a smooth complex projective variety

There is an analog of the Kodaira vanishing theorem for such a metric, on compact or noncompact complex manifolds.

[7] This led to the first effective criteria for a line bundle on a complex projective variety

[8] Demailly used the technique of jet differentials introduced by Green and Phillip Griffiths to prove Kobayashi hyperbolicity for various projective varieties.

For example, Demailly and El Goul showed that a very general complex surface

[12] Demailly was elected a correspondent of the French Academy of Sciences in 1994 and then became a permanent member in 2007.