Richard Rado was a distinguished German-born British mathematician who made foundational contributions to combinatorics and graph theory. Born in Berlin in 1906, he earned his first doctorate from the University of Berlin in 1933 under Issai Schur, subsequently fleeing Nazi persecution as a Jewish scholar and continuing his studies at the University of Cambridge where he completed a second PhD under G.H. Hardy in 1935. His academic career began at the University of Sheffield in 1936, where he served as Lecturer until 1947, after which he became Reader at King's College London for seven years. In 1954, Rado assumed the position of Professor of Pure Mathematics at the University of Reading, where he remained until his retirement in 1971, establishing himself as a leading figure in discrete mathematics.
Rado's most influential work centered on combinatorial mathematics, where he developed fundamental results in Hall's theorem, Ramsey's theorem, and the Rado selection principle, alongside significant contributions to matroid theory and transversal theory. His collaboration with Paul Erdős produced the partition calculus framework and the seminal Erdős–Ko–Rado theorem published in 1961, which established crucial bounds on intersecting families of sets and became a cornerstone of extremal set theory. He also rediscovered the remarkable Rado graph in 1964, a countably infinite universal graph that contains all countably infinite graphs as induced subgraphs and now bears his name. Beyond combinatorics, Rado made important contributions to the theory of sequences and series, inequalities, geometry, and measure theory, particularly through his work with Besicovitch.
Rado's approach to mathematics emphasized elegance and generality, as Erdős noted that he always tried to formulate his results at their natural level of generality to exhibit their full power without obscuring content through over-elaboration. His scholarly impact was recognized with his election as a Fellow of the Royal Society in 1978, one of the highest honors in British science. Additionally, he received an honorary doctorate from the Free University of Berlin in 1981, a meaningful acknowledgment from his native city decades after his forced departure. The enduring significance of his work continues to shape modern combinatorics, with concepts like the Erdős–Ko–Rado theorem and Rado graph remaining central to contemporary research in discrete mathematics and theoretical computer science.
