Kenneth Joseph Arrow. 23 August 1921—21 February 2017

Kenneth Arrow was a mathematical economist and political scientist who made many ground-breaking contributions to the theory of economics and social values. His great mathematical ability led him to introduce new approaches to theoretical economics and in particular to a series of fundamental theorems in the discipline. These included the Arrow Impossibility Theorem, the two fundamental theorems of welfare economics and the existence of a competitive equilibrium. For these and many other contributions he was awarded the 1972 Nobel Prize in Economics shared with Sir John Hicks. He took a particular interest in computation and computability in economics. He was active and very productive as a researcher for over seven decades and was renowned as a generous and inspiring teacher and colleague.