Professor Klaus Bierstedt, who was elected a member of the London Mathematical Society on 21 May 1976, died on 23 May 2009, aged 64.
Reinhold Meise writes: Klaus Bierstedt was born and grew up in Mainz. There he studied mathematics and physics at the Johannes Gutenberg University, where he wrote his diploma and doctoral theses under the direction of B. Gramsch. In the early 1970s he held positions as assistant and as associate professor at the universities of Kaiserslautern and Mainz. He became a full professor at the University of Paderborn in 1974.
Klaus published 57 articles in various areas of functional analysis and organized or initiated many international conferences. He acted as a referee for many mathematical journals and was a member of the editorial committee of Mathematische Nachrichten and the Arab Journal of Mathematical Sciences. For eight years Klaus was a member of the council of the German Mathematical Society (DMV) and for many years a member of the coordinating committee of Zbl. Math. and vice-chair of the FIZ Karlsruhe. Since 1988 he was a corresponding member of the Société Royale des Sciences de Liège, Belgium, and since 1999 of the Real Academia de Ciencias in Madrid, Spain.
Klaus held visiting positions at universities in the United States, Brazil and Spain. He liked soccer, musicals and travelling a lot. The mathematical community has lost a great colleague.
Dr Kathleen Collard, who was elected a member of the London Mathematical Society on 25 January 1945, died on 2 June 2009, aged 93.
Dave Johnson and Bob Lockhart write: After attending Birkenhead Council Secondary School for 10 years, Kathleen won a State Scholarship and Founder’s Entrance scholarship to Royal Holloway College, London, in 1934. Having achieved distinction in both BSc and MSc, she proceeded on a postgraduate studentship to work with Max Born at the University of Edinburgh, where she submitted her PhD thesis ’On the extra spots on the Laue photograph’ in June 1941. During the war she was partially deafened as a result of a bomb explosion, a disability that seemed to have virtually no effect on her. She moved to Oxford in 1942 as Lecturer in Mathematics at Somerville College, where she was elected a Fellow in 1947 and served as Dean for eight years. She married her first husband, Dr Basil Geoghegan, just before his death in January 1954, an experience which prompted her to seek experiences beyond those of British Academe.
In 1955, she became Professor of Mathematics at Ibadan, Nigeria, where she married Dr Patrick John Collard and had two children, Ann and James. She returned to the UK in 1965, taking up an appointment in the Mathematics Department at the University of Nottingham as well as the Wardenship of Cavendish Hall. During her time as a warden she was awarded the OBE for her work in improving access to university education to the disabled. She went from there to Unitech in Lae, Papua New Guinea, where she occupied a Chair 1980–87, one of the happiest times of her life. She was a very active and popular professor of mathematics, particularly encouraging mathematical work that related directly to the country, such as Glen Lean’s encyclopaedic survey of Melanesian counting systems.
On her return to the UK, she lived near her family in Ilkeston, travelling widely in Europe, China and South Africa. Kathleen had a distinguished academic career and will be remembered by those who knew her for her adventurous spirit and warm and generous personality. She will be sorely missed by her family, friends and colleagues.
[We are grateful to Pauline Adams of Somerville and Vicky Holmes of Royal Holloway, and especially James Collard, for providing much valuable information.]
MARIJKE VAN GANS
Dr Marijke van Gans, who was elected a member of the London Mathematical Society on 18 February 2003, died on 21 April 2009, aged 53.
Robert Curtis writes: Marijke was a highly original and exceptionally talented scholar and mathematician, who had become known internationally as a solver of demanding mathematical problems on the internet. She was a brilliant computer programmer and an inspirational mathematical expositor, as is witnessed by the many accolades to her on the web from people who have been enlightened by her insight.
She was born at Harns or Harlingen in the Netherlands but studied at the University of London from 1987–90, and later lived in Ireland, England and Scotland. Indeed, at one point she was one third of the winning Compuserve SCIMATH Forum Team whilst living on the Isle of Bute. One imagines her in a croft with a state-of-the-art laptop computer, but few other creature comforts! The other two members of her team lived in Wigan and in Memphis, Tennessee, and no two of the trio had ever met face to face.
Encouraged and commended by the many people she had impressed through her problem-solving online, she came to the University of Birmingham in 2004 to research into combinatorics under the supervision of Robert Curtis. Her thesis was entitled Topics in trivalent graphs and she was awarded the PhD degree in 2007.
She fell ill earlier this year and, sadly, the seriousness of her condition was not immediately recognised. The disease proved particularly virulent and she died rapidly; thus a unique mathematical talent is lost to us.