Ulam participated in the creation of a hydrogen bomb as part of the Los Alamos Laboratory nuclear project. From the publication of his first paper as a student in 1929 until his death, Ulam was constantly writing on mathematics. The list of Ulam's publications includes more than 150 papers. Topics represented by a significant number of papers are: set theory (including measurable cardinals and abstract measures), topology, functional analysis, transformation theory, ergodic theory, group theory, projective algebra, number theory, combinatorics, and graph theory.