Question: In between Alexander Razborov and Jakow Trachtenberg who was a Jewish mathematician?
Context: Ernst Paul Heinz Pruefer (10 November 1896 – 7 April 1934) was a German Jewish mathematician born in Wilhelmshaven.  His major contributions were on abelian groups, algebraic numbers, knot theory and Sturm–Liouville theory. Mikhail Iosiphovich Kadets (Russian: Михаил Иосифович Кадец , Ukrainian: Михайло Йосипович Кадець , sometimes transliterated as Kadec, November 30, 1923 – March 7, 2011) was a Soviet-born Jewish mathematician working in analysis and the theory of Banach spaces. Felix Bernstein (24 February 1878 in Halle, Germany – 3 December 1956 in Zurich, Switzerland), was a German Jewish mathematician known for proving the Schröder–Bernstein theorem central in set theory in 1896, and less well known for demonstrating the correct blood group inheritance pattern of multiple alleles at one locus in 1924 through statistical analysis. Giulio Benedetto Isacco Vivanti (24 May 1859 – 19 November 1949) was an Italian Jewish mathematician.  He spent most of his academic career at the University of Pavia and University of Milan. Katia Mann (born "Katharina Hedwig Pringsheim;" July 24, 1883 – April 25, 1980) was the youngest child and only daughter (among four sons) of the German Jewish mathematician and artist Alfred Pringsheim and his wife Hedwig Pringsheim, who was an actress in Berlin before her marriage.  Katia was also a granddaughter of the writer and women's rights activist Hedwig Dohm.  Her twin brother Klaus Pringsheim was a conductor, composer, music writer and music pedagogue, active in Germany and Japan.  She married the writer Thomas Mann. David Moiseevich Khorol (Russian: Давид Моисеевич Хорол ) (February 4, 1920 — February 19, 1990) was Soviet Jewish mathematician and aviation and rocket designer, professor, "doktor" of technical sciences.  His last position was deputy general director of the Central Design Bureau "Geophysics" (ЦКБ «Геофизика»), known for its rocket design. The Trachtenberg system is a system of rapid mental calculation.  The system consists of a number of readily memorized operations that allow one to perform arithmetic computations very quickly.  It was developed by the Russian Jewish engineer Jakow Trachtenberg in order to keep his mind occupied while being held in a Nazi concentration camp. Aleksandr Aleksandrovich Razborov (Russian: Алекса́ндр Алекса́ндрович Разбо́ров ; born February 16, 1963), sometimes known as Sasha Razborov, is a Soviet and Russian mathematician and computational theorist. Steven Rudich (born October 4, 1961) is a professor in the Carnegie Mellon School of Computer Science.  In 1994, he and Alexander Razborov proved that a large class of combinatorial arguments, dubbed natural proofs were unlikely to answer many of the important problems in computational complexity theory.  For this work, they were awarded the Gödel prize in 2007.  He also co-authored a paper demonstrating that all currently known NP-complete problems remain NP-complete even under AC or NC reductions. Jakow Trachtenberg (17 June 1888 – 1953) was a Jewish mathematician who developed the mental calculation techniques called the Trachtenberg system.
Answer: Jakow Trachtenberg