| Irvin S. Cohen | |
| Birth Date: | 1917 |
| Death Date: | 14 February 1955 |
| Nationality: | American |
| Field: | Mathematics |
| Known For: | Cohen-Macaulay rings, Cohen structure theorem, Cohen-Seidenberg theorems, unmixedness theorem, Cohen rings |
| Work Institution: | Massachusetts Institute of Technology |
| Alma Mater: | Johns Hopkins University (Ph.D., 1942) |
| Doctoral Advisor: | Oscar Zariski |
| Doctoral Students: | R. Duncan Luce |
Irvin Sol Cohen (1917 – February 14, 1955) was an American mathematician at the Massachusetts Institute of Technology who worked on local rings. He was a student of Oscar Zariski at Johns Hopkins University.
In his thesis he proved the Cohen structure theorem for complete Noetherian local rings. In 1946 he proved the unmixedness theorem for power series rings. As a result, Cohen–Macaulay rings are named after him and Francis Sowerby Macaulay.
Cohen and Abraham Seidenberg published their Cohen–Seidenberg theorems, also known as the going-up and going-down theorems. He also coauthored articles with Irving Kaplansky. One of his doctoral students was R. Duncan Luce.
Cohen died unexpectedly in 1955 one week after having visited Zariski in Cambridge, apparently from suicide. Many years later Zariski said of his death: