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 16 figures behind the modern work who have died, 6 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

• Patrick X. Gallagher (1935-2019): Pioneered large sieve theory and invented the larger sieve; his 1976 short-interval work turned the Hardy-Littlewood prime-tuple heuristics into the Poisson model used to predict primes between consecutive squares
• 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
• Christopher Hooley (1928-2018): Hooley's theorem on Artin's conjecture under GRH; a leading figure in applying the Selberg sieve to problems on primes
• Anatoly Karatsuba (1937-2008): Analytic number theory, exponential sums, and the distribution of primes in short intervals; founder of a major Russian school
• Stanisław Knapowski (1931-1967): With Turan developed comparative prime number theory and studied sign changes of pi(x) - li(x)
• Edmund Landau (1877-1938): Posed the four problems on primes (Goldbach, twin primes, Legendre's conjecture, and n^2+1 primes) as unattackable at the 1912 International Congress of Mathematicians; foundational figure in analytic number theory
• Aleksandr Fedorovich Lavrik (1927-2010): Approximate functional equations for L-functions and work on the ternary Goldbach problem and primes in short intervals
• Shituo Lou (1941-2015): With Qi Yao proved a Chebyshev-type prime number theorem in short intervals of length x^theta for theta greater than 11/20 (1993), one of the sharpest unconditional results on the interval lengths Legendre's conjecture asks about
• 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
• Charles-Jean de la Vallée Poussin (1866-1962): Co-proved the Prime Number Theorem (1896) and established the classical zero-free region of the Riemann zeta-function
• Hans-Egon Richert (1924-1993): Co-author of the standard monograph Sieve Methods (with Halberstam), the foundational reference for work on prime gaps
• Georg Johann Rieger (1931-2021): Additive number theory, the Goldbach and Waring problems, and the distribution of squarefree numbers
• 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
• Pál Turán (1910-1976): Created the power-sum (Turan) method and applied it to the zeros of the zeta-function and to comparative prime number theory
• Yuan Wang (1930-2021): The Wang (1+4) result and major contributions to the circle method and sieve theory for additive prime problems