Paul Cohen was an American mathematician born in a Jewish immigrant family in New Jersey on April 2, 1934. His father’s name was Abraham Cohen while mothers’ name was Minnie Cohen and they had got separated when Paul was just nine years old. He was raised by her mother in Brooklyn since then. Paul had developed understanding of mathematics from a very young age that allowed him to pursue a career in the same field.
In his early life Paul attended the Stuyvesant High School in New York City and graduated at the age of sixteen in 1950. The same year he attended the Brooklyn College but soon he discovered that he could earn a graduate degree from the University of Chicago without completing his undergraduate program. Utilizing the opportunity, he left his college in 1953 to pursue his masters from the University of Chicago. There he started research work on Number theory under André Weil and completed his masters in 1954. He then completed his thesis on Topics in the Theory of Uniqueness of Trigonometric Series which was supervised by the great mathematician Antoni Zygmund and received his doctorate in 1958. Along with his thesis, Cohen also worked at the University of Rochester as a mathematics instructor during the year 1957. After his PhD, Cohen joined the Institute for Advanced Study at Princeton as a research fellow in 1958 and worked there for two years. Two of his most popular publications from this time period include Factorization in group algebras and On a conjecture of Littlewood and idempotent measures.
Cohen joined the Stanford University in 1961 as an assistant professor of mathematics, got promoted to associate professor in 1962 and to full professor in 1964. During his professorship at Stanford, Cohen received many awards, these include;
- Alfred P Sloan research fellowship at Stanford in 1962.
- Bôcher Memorial Prize for his paper On a conjecture of Littlewood and idempotent measures from the American Mathematical Society in 1964.
- Fields Medal in mathematics for his work on set theory at the International Congress of Mathematicians in Moscow in 1966.
- National Medal of Science for his works in mathematical logic in 1967.
- His speech on Idempotent measures and homomorphisms of group algebras at the International Congress of Mathematicians in Stockholm.
Cohen also joined the societies of his field which were;
- National Academy of Sciences
- American Academy of Arts and Sciences
- London Mathematical Society
In 1962, Cohen addressed first of the Hilbert’s 23 problems that were presented by David Hilbert in 1900. This problem was to prove Cantor’s continuum hypothesis. Cohen worked on this theorem and on axiom of choice and proved them through his self developed concept of ‘forcing’. Two of his papers; the independence of the continuum hypothesis published in 1963 and the independence of the continuum hypothesis. II published in 1964 and a lecture Independence results in set theory delivered at the international symposium on the ‘Theory of Models’ at Berkeley in 1963 were on his proof for the independence of both continuum hypothesis and axiom of choice from the Zermelo-Fraenkel set theory (ZFC). Cohen’s new concept of ‘forcing’ was approved by Kurt Gödel in 1963.
Cohen also did a lot of work in differential equations and harmonic analysis. One of the formal students of Cohen, Peter Sarnak, who was also a mathematics professor at Princeton, considered Cohen’s contributions to be covering a wide range of mathematical subjects.
Cohen not only solved Hilbert’s first problem but also dared to address the eighth of the 23 problems; the Riemann hypothesis in 1969. He worked on this hypothesis till his death in 2007, but could not present a final solution. However, his researches and findings were used by other mathematicians.
Cohen retired from the Stanford University in 2004 but did not discontinue teaching until his death in 2007. He died on March 23, in Stanford, California.