1878 – 1957
Leopold Löwenheim was a German mathematician and logician best known for his foundational contributions to mathematical logic in the early 20th century. His 1915 paper 'Über Möglichkeiten im Relativkalkül' established what would become the Löwenheim-Skolem theorem, a cornerstone result in model theory demonstrating that first-order theories with infinite models have models of every infinite cardinality.
Proved the original Löwenheim theorem (1915), precursor to the Löwenheim-Skolem theorem
Pioneered early work in model theory and the calculus of relatives
Contributed to the development of first-order logic as a distinct system
Advanced Schröder's algebra of logic tradition