Albert Thoralf Skolem

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Born: 23 May 1887 in Sandsvaer, Norway
Died: 23 March 1963 in Oslo, Norway

Thoralf Skolem worked on Diophantine equations, mathematical logic, group theory, lattice theory and set theory. In 1912 he produced a description of a free distributive lattice. He made refinements to Zermelo's axiomatic set theory, publishing work in 1922 and 1929.

Skolem extended work by Löwenheim (1915) to give the Löwenheim- Skolem theorem, which states that if a theory has a model then it has a countable model. From 1933 he did pioneering work in metalogic and constructed a nonstandard model of arithmetic.

He also developed the theory of recursive functions as a means of avoiding the so-called paradoxes of the infinite.