Guy David (mathematician)

Guy David (born 1957) is a French mathematician, specializing in analysis. David studied from 1976 to 1981 at the École normale supérieure, graduating with Agrégation and Diplôme d'études approfondies (DEA). At the University of Paris-Sud (Paris XI) he received in 1981 his doctoral degree (Thèse du 3ème cycle) and in 1986 his higher doctorate (Thèse d'État) with thesis Noyau de Cauchy et opérateurs de Caldéron-Zygmund supervised by Yves Meyer. David was from 1982 to 1989 an attaché de recherches (research associate) at the Centre de mathématiques Laurent Schwartz of the CNRS. At the University of Paris-Sud he was from 1989 to 1991 a professor and from 1991 to 2001 a professor first class, and is since 1991 a professor of the Classe exceptionelle. David is known for his research on Hardy spaces and on singular integral equations using the methods of Alberto Calderón. In 1998 David solved a special case of a problem of Vitushkin. Among other topics, David has done research on Painlevé's problem of geometrically characterizing removable singularities for bounded functions; Xavier Tolsa's solution of Painlevé's problem is based upon David's methods. With Jean-Lin Journé he proved in 1984 the T(1) Theorem, for which they jointly received the Salem Prize. The T(1) Theorem is of fundamental importance for the theory of singular integral operators of Calderón-Zygmund type. David also did research on the conjecture of David Mumford and Jayant Shah in image processing and made contributions to the theory of Hardy spaces; the contributions were important for Jones' traveling salesman theorem in . David has written several books in collaboration with Stephen Semmes. 1986 — Invited Speaker, International Congress of Mathematicians, Berkeley, California 1987 — Salem Prize 1990 — Prix IBM France 1999 — Foreign Honorary Member of the American Academy of Arts and Sciences 2001 — Silver medal of the CNRS 2004 — Ferran Sunyer i Balaguer Prize for the article Singular sets of minimizers for the Mumford-Shah functional.