Set theory
Who
Founded by Georg Cantor (whose Jewish ancestry is debated) and later axiomatized with Abraham Fraenkel, an observant Jew and co-founder of the Hebrew University.
When
1874–1922
Where
Germany
Set theory, founded by Georg Cantor in the 1870s, became the foundational language of modern mathematics; Cantor himself referred at times to Jewish ancestry, though this remains debated. Its standard axiomatic system, Zermelo–Fraenkel set theory, bears the name of Abraham Fraenkel, an observant Jewish mathematician who later helped establish the Hebrew University of Jerusalem.
Sources
Part of “The Gifts of the Jews” — verified Jewish contributions to the world, with sources.