Francesco Severi (13 April 1879 – 8 December 1961) was an Italian mathematician. He was the chair of the committee on Fields Medal on 1936, at the first delivery.
Severi was born in Arezzo, Italy. He is famous for his contributions to algebraic geometry and the theory of functions of several complex variables. He became the effective leader of the Italian school of algebraic geometry. Together with Federigo Enriques, he won the Bordin prize from the French Academy of Sciences.
He contributed in a major way to birational geometry, the theory of algebraic surfaces, in particular of the curves lying on them, the theory of moduli spaces and the theory of functions of several complex variables. He wrote prolifically, and some of his work (following the intuition-led approach of Federigo Enriques) has subsequently been shown to be not rigorous according to the then new standards set in particular by Oscar Zariski and Andre Weil. Although many of his arguments have since been made rigorous, a significant fraction were not only lacking in rigor but also wrong (in contrast to the work of Enriques, which though not rigorous was almost entirely correct). At the personal level, according to he was easily offended, and he was involved in a number of controversies. Most notably, he was a staunch supporter of the Italian fascist regime of Benito Mussolini and was included on a committee of academics that was to conduct an anti-semitic purge of all scholarly societies and academic institutions.
His childhood was marked by the death of his father, which occurred when he was 9 years old. This had serious economic repercussions on their family. Although he had to earn a living while conducting private lessons, Francesco Severi managed to continue his studies and enroll in the engineering course at the University of Turin. Due to the influence of courses by Corrado Segre, Severi quickly found a passion for pure mathematics.
In 1900, he completed his training with a thesis in the geometry of numbers, which would later become his favorite subject.