J. W. S. Cassels

John William Scott Cassels (born July 11, 1922) is a leading British mathematician.

His academic career was interrupted in World War II when he was involved in cryptography at Bletchley Park. After the war he became a research student of Louis Mordell, at the University of Cambridge.

He initially worked on elliptic curves. After a period when he worked on geometry of numbers and diophantine approximation, he returned in the later 1950s to the arithmetic of elliptic curves, writing a series of papers connecting the Selmer group with Galois cohomology and laying some of the foundations of the modern theory of infinite descent. His best-known single result may be the proof that the Tate-Shafarevich group , if it is finite, must have order that is a square; the proof being by construction of an alternating form.

His mathematical style is mainly as a problem solver, prepared for example to tackle individual Diophantine equations by algebraic number theory and p-adic methods . His publications number around 200 papers.

Awards

• Fellow of the Royal Society 1963
• Royal Society Sylvester Medal 1973
• De Morgan Medal 1986

External links

• MacTutor biography