Viscount  Pierre Deligne  (b. 1944) Belgian MathematicianProved Weil's conjectures, in 1974.

Vert, three hens Proper in fess.

Motto:   La première va devant.   ("The first one leads.")
Crest:   A dodecahedron Or.   Supporters:   Two trees Vert trunked Argent.

Deligne is one of the greatest mathematicians of the twentieth century.  In 2006,  Pierre René Deligne  was ennobled by Albert II, King of the Belgians.  On that occasion,  the new  Vicomte Deligne  designed for himself the above coat of arms, which is inspired by the following nursery rhyme  (sing it to the tune of "Twinkle twinkle little star").  This rhyme is intended to teach children the meaning of a few simple words.  As such, it appears to adults as a succession of tautologies.  Deligne argues that mathematical discourse proceeds in much the same way...

 Quand trois poules vont aux champs, La première va devant, La deuxième suit la première, La troisième est la dernière.  Quand trois poules vont aux champs, La première va devant. As three hens head for the fields, The first one leads, The second follows the first, The third one is last.  As three hens head for the fields, The first one leads.

At right is the original artwork for a Belgian stamp honoring Pierre Deligne.  The actual stamp was issued in 2007 in a different denomination  (0.70 instead of 0.60 euros).  The relation it features was conjectured by Ramanujan and proved by Pierre Deligne in 1974.  That inequality gives an upper bound, for a  prime  argument  (p)  of the absolute value of Ramanujan's  tau function  (A000594).  The tau function  (t)  is an important arithmetical function which was proved to be  multiplicative  in 1917,  by Louis J. Mordell (1888-1972).  It's best defined via its  generating function :

 ¥ t(n) z n     =     z ¥ ( 1-z k ) 24 å Õ n=0 k=1 =     z  -  24 z2  +  252 z3  -  1472 z4 +  4830 z5  +  ...

Incidentally, this yields  t(0) = 0  (which is how the range of any multiplicative function is always extended down to  0, if one bothers to do so).

Pierre Deligne was born on October 3, 1944 in Etterbeek  (Greater Brussels, Belgium).  After graduating from secondary school in 1962, he became a student at the  Free University of Brussels  but managed to spend most of the academic year 1965-1966 as a  pensionnaire étranger  at the  Ecole Normale Supérieure  in Paris  (ENS, rue d'Ulm).  In 1967-68, Pierre Deligne was concurrently a junior scientist  (aspirant)  at the Belgian FNRS and a guest at the  Institut des Hautes Études Scientifiques  (IHES)  at Bures-sur-Yvette  (France)  where he worked under Alexander Grothendieck (1928-2014).  Deligne received a doctorate from the University of Brussels in 1968 and also from the university of Paris Sud (Orsay, located next to IHES).  Pierre Deligne was awarded a French  doctorat d'Etat  in 1972.

On February 1970, Pierre Deligne became a permanent member of IHES.  Concurrently, he was a Member  (1972-73, 1976-77)  and Visitor (1981-82) in the School of Mathematics at the  Institute for Advanced Study  (IAS, Princeton, New Jersey).  He was appointed to a faculty position there in September 1984 and transferred to Emeritus status in January 2008.

Pierre Deligne was awarded the  François Deruyts Prize  from the Belgian Royal Academy in 1974, the  Henri Poincaré Medal  from the French Académie des Sciences  in 1974, the  Dr. A. De Leeuw-Damry-Bourlart Prize  (Belgium's FNRS Prize)  in 1975 and the  Fields Medal  in 1978.  He received the  Crafoord Prize  in 1988  (jointly with Alexandre Grothendieck, who declined it).  He was awarded the  Balzan Prize  in 2004, the Wolf Prize in 2008 and, finally, the  Abel prize  in 2013.

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