Jean-Louis Nicolas is a French number theorist. He is the namesake (with Paul Erdős) of the

Erdős–Nicolas number In number theory, an Erdős–Nicolas number is a number that is not perfect, but that equals one of the partial sums of its divisors. That is, a number is Erdős–Nicolas number when there exists another number such that : \sum_d=n. The fir ...

s, and was a frequent co-author of Erdős, who would take over the desk of Nicolas' wife Anne-Marie (also a mathematician) whenever he would visit. Nicolas is also known for his research on

partitions Partition may refer to: Computing Hardware * Disk partitioning, the division of a hard disk drive * Memory partition, a subdivision of a computer's memory, usually for use by a single job Software * Partition (database), the division of a ...

,. and for his unusual proof that there exist infinitely many ''n'' for which :

\varphi(n) < e^\frac

where

\varphi(n)

is Euler's totient function and γ is

Euler's constant Euler's constant (sometimes also called the Euler–Mascheroni constant) is a mathematical constant usually denoted by the lowercase Greek letter gamma (). It is defined as the limiting difference between the harmonic series and the natural ...

: he proved this bound unconditionally by providing two different proofs, one in the case that the Riemann hypothesis holds and another in the case that it fails. Nicolas earned his Ph.D. in 1968 as a student of

Charles Pisot Charles Pisot (2 March 1910 – 7 March 1984) was a French mathematician. He is chiefly recognized as one of the primary investigators of the numerical set associated with his name, the Pisot–Vijayaraghavan numbers. He followed the classical p ...

. He works at

Claude Bernard University Lyon 1 Claude Bernard University Lyon 1 (french: link=no, Université Claude-Bernard Lyon 1, UCBL) is one of the three public universities of Lyon, France. It is named after the French physiologist Claude Bernard and specialises in science and technol ...

. A conference in honor of Nicolas' 60th birthday was held on January 14–19, 2002 at the

Centre International de Rencontres Mathématiques The Centre International de Rencontres Mathématiques (CIRM) is a mathematics research institute associated with the Centre National de la Recherche Scientifique (CNRS) and the Société Mathématique de France (SMF). It is located in Luminy, Marse ...

Marseille Marseille ( , , ; also spelled in English as Marseilles; oc, Marselha ) is the prefecture of the French department of Bouches-du-Rhône and capital of the Provence-Alpes-Côte d'Azur region. Situated in the camargue region of southern Fra ...

. The proceedings of the conference were published as a

festschrift In academia, a ''Festschrift'' (; plural, ''Festschriften'' ) is a book honoring a respected person, especially an academic, and presented during their lifetime. It generally takes the form of an edited volume, containing contributions from the h ...

in ''The Ramanujan Journal''..

References

{{DEFAULTSORT:Nicolas, Jean-Marie 20th-century French mathematicians 21st-century French mathematicians Year of birth missing (living people) Living people Number theorists Academic staff of the University of Lyon