Percy John Heawood

Percy John Heawood (8 September 1861 – 24 January 1955 ) was a British mathematician, who concentrated on graph colouring.

Life He was the son of the Rev. John Richard Heawood of Newport, Shropshire, and his wife Emily Heath, daughter of the Rev. Joseph Heath of Wigmore, Herefordshire; and a first cousin of Oliver Lodge, whose mother Grace was also a daughter of Joseph Heath. He was educated at Queen Elizabeth's School, Ipswich, and matriculated at Exeter College, Oxford in 1880, graduating B.A. in 1883 and M.A. in 1887.

Durham University awards an annual Heawood Prize to a student graduating in Mathematics whose performance is outstanding in the final year.

Works

Heawood devoted himself to the four colour theorem and related questions. In 1890 he exposed a flaw in Alfred Kempe's proof, that had been considered as valid for 11 years. The four colour theorem being an open question again, he established the weaker five colour theorem. The four colour theorem itself was finally established by a computer-based proof in 1976.

Heawood also studied colouring of maps on higher surfaces and established the upper bound on the chromatic number of such a graph in terms of the connectivity (genus, or number of handles) of the surface. This upper bound was proved only in 1968 to be the actual maximum.

Writing in the Journal of the London Mathematical Society, G. A. Dirac wrote:

Family Heawood married in 1890 Christiana Tristram, daughter of Henry Baker Tristram; they had a son and a daughter.