In Memoriam

Researchers in this directory who are no longer with us

The Top 100 and the regional pages list living researchers only, so the directory stays accurate for anyone using it to make contact. This page is the one place the directory remembers the 21 figures behind the modern work who have died, 11 of whom also carry a rank in this site's ranked pool.

This is a curated list, not a computed one. Who appears here is an editorial judgement: a person is listed because their work matters to this problem, and every entry is hand-checked. The Rank column shows the site's composite ranked-pool rank for those who carry one, so the quantitative signal stays visible, but it is a guide to the judgement rather than the thing that decides it. A dash means the person is not in the ranked pool at all, which is the normal case for careers that predate the arXiv and OpenAlex record the pipeline reads from. Sort any column; dashes always sort to the bottom.

Contributions

• Jean Bourgain (1954-2018): Fields Medal 1994; sum-product estimates in finite fields and Bourgain-Gamburd expansion, with sharp consequences for exponential sums over primes
• Jingrun Chen (1933-1996): Chen's theorem; also proved that infinitely many n give n^2+1 a prime or a product of two primes
• Javier Cilleruelo (1961-2016): Proved the asymptotic law for the least common multiple of the quadratic sequence n^2+1 (Compositio Mathematica, 2011), the sharpest general result on the multiplicative structure of the very sequence Landau's fourth problem concerns
• Harold Davenport (1907-1969): Multiplicative Number Theory and major advances in the Hardy-Littlewood circle method for additive prime problems
• Paul Erdős (1913-1996): Foundational and prolific contributor to additive and combinatorial number theory; posed and funded many of the prize problems that drive modern work on prime distribution
• Patrick X. Gallagher (1935-2019): Pioneered large sieve theory and invented the larger sieve; his singular-series work underlies the Hardy-Littlewood prime-tuple heuristics
• George Greaves (1941-2008): Sieve theorist at Cardiff and author of "Sieves in Number Theory" (Springer, 2001); his weighted sieve results bear directly on almost-prime values of polynomials
• Heini Halberstam (1926-2014): Co-author of the standard monograph Sieve Methods (with Richert); the Elliott-Halberstam conjecture is central to modern work on prime gaps
• C. Hooley (1928-2018): Author of the Cambridge tract Applications of Sieve Methods to the Theory of Numbers (1976); his results on the greatest prime factor of a quadratic polynomial bear directly on primes of the form n^2+1
• Yuri Linnik (1915-1972): The large sieve, the dispersion method, and Linnik's theorem on the least prime in an arithmetic progression
• Ming-Chit Liu (1937-2023): Set an effective record on the ternary Goldbach problem (with Tianze Wang, 2002); analytic number theory at HKU
• Florian Luca (1969-2026): Ranked 2nd on this board at the time of his death in late July 2026; more than 800 papers on Diophantine equations, recurrence sequences and the arithmetic of polynomial values
• Richard A. Mollin (1947-2014): Calgary number theorist, twelve books on number theory and cryptography, six Killam Resident Fellowships and a founding role in the Canadian Number Theory Association; his work on quadratic fields and continued fractions bears on prime-producing polynomials
• Chengdong Pan (1934-1997): Proved the (1,5) case toward Goldbach's conjecture (1962) and the (1,4) case (1963, independently and with Barban and Wang Yuan); founder of the Shandong University school of analytic number theory and an academician of the Chinese Academy of Sciences
• Georg Johann Rieger (1931-2021): Additive number theory, the Goldbach and Waring problems, and the distribution of squarefree numbers
• Andrzej Schinzel (1937-2021): Schinzel's Hypothesis H, which predicts infinitely many primes of the form n^2+1 and generalizes many prime-representation conjectures
• Wolfgang Schwarz (1934-2013): Mean-value theorems for arithmetic functions and Ramanujan expansions; co-organizer of the Oberwolfach analytic number theory meetings
• Atle Selberg (1917-2007): Fields Medalist; the Selberg sieve is a foundational tool in all modern work on the distribution of primes
• Askold Ivanovich Vinogradov (1929-2005): The Bombieri-Vinogradov theorem on the distribution of primes in arithmetic progressions on average
• Yuan Wang (1930-2021): The Wang (1+4) result and major contributions to the circle method and sieve theory for additive prime problems
• Dieter Wolke (1942-2015): Freiburg analytic number theorist working on additive prime number theory and the distribution of primes