Ioan James

Ioan Mackenzie James FRS (23 May 1928 – 21 February 2025) was a British mathematician working in the field of topology, particularly in homotopy theory.

James was born in Croydon, Surrey, England, and was educated at St Paul's School, London and Queen's College, Oxford. In 1953 he earned a D. Phil. from the University of Oxford for his thesis entitled Some problems in algebraic topology, written under the direction of J. H. C. Whitehead.

In 1957 he was appointed reader in pure mathematics, a post which he held until 1969. From 1959 until 1969 he was a senior research fellow at St John's College, Oxford. He held the Savilian Chair of Geometry at the University of Oxford from 1970 to 1995. He was a professor emeritus, and later an honorary fellow of St John's.

He was elected a Fellow of the Royal Society in 1968. In 1978 the London Mathematical Society awarded him the Senior Whitehead Prize, which was established in honour of his doctoral supervisor, Whitehead. In 1984 he became President of the London Mathematical Society.

James married Rosemary Stewart, a writer and researcher in business management and healthcare management, in 1961. She died in 2015, aged 90. James died on 21 February 2025, aged 96.