**John Knopfmacher** was a South African mathematician who worked mainly in number theory.

- Walter Knopfmacher was born on Berlin on 6 August 1899 and attended the Koellnisches Gymnasium and the Friedrichs-Werdersche Oberrealschule in Berlin.
- John attended primary school at Yeoville Boys' School, and high school at Athlone Boys' High.
- Although John was a good student, he was not brilliant in high school.
- After graduating from High School, Knopfmacher entered the University of the Witwatersrand in Johannesburg to study accountancy.
- By the time Knopfmacher was in his third year of study at the University of the Witwatersrand his lecturers were so impressed with his work that he was asked to give some lectures to first year students.
- Knopfmacher was awarded a Ph.D. in 1965 for his thesis Extensions in Varieties of Groups and Algebras.
- Knopfmacher was offered promotion but was reluctant to accept it.
- In 1978 Knopfmacher was offered a full Professorship of Mathematics at the University of the Witwatersrand.
- In 1984 Knopfmacher agreed that he would accept the position as Head of the Mathematics Department and the City of Johannesburg Chair.
- Beginning in 1987 John and Arnold published joint papers, their first being A new infinite product representation for real numbers.
- As Head of Mathematics at the University of the Witwatersrand, Knopfmacher made efforts to increase the research profile of the department.
- In 1997 Knopfmacher retired from the University of the Witwatersrand and moved to Melbourne, Australia.
- It was published in 2001, two years after Knopfmacher's death.
- We now have a rather mature and rich theory which is well developed, and it is therefore time to give a readable account of the theory in a new book." So this new monograph is a largely increased, totally new version of the above-cited monograph from 1979, and many of the new results are due to the second author, Zhang (and to A Hildebrand, K-H Indlekofer, A Knopfmacher, J Knopfmacher, E Manstavičius, G Tenenbaum, R Warlimont, ...
- In 1999 Knopfmacher went to Graz, Austria, as a Visiting Professor.
- John worked many hours every day at the department, and he also visited various places in Graz as a tourist.
- Among the honours Knopfmacher received, we mention the medal for lifetime achievement from the South African Mathematical Society in 1995, and his election to a fellowship of the Royal Society of South Africa in 1991.
- In September 1999 the Council of the University of the Witwatersrand agreed to rename the Centre Knopfmacher founded in 1992 in his honour as the John Knopfmacher Centre for Applicable Analysis and Number Theory.

Born 20 January 1937, Johannesburg, Transvaal, South Africa. Died 29 May 1999, Graz, Austria.

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African, Origin South Africa

**O’Connor, John J; Robertson, Edmund F**: MacTutor History of Mathematics Archive