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- Brief professional biography
- Commitment to international and ICMI work
- Essential primary bibliography
- Obituaries

Bent Christiansen was born on 7 May 1921 in Aalborg (Denmark). He studied, from 1939 to 1944, mathematics, physics, chemistry, and astronomy at the University of Copenhagen. After his university studies he became a mathematics teacher committed to improving teaching methods and thus giving more students competence in, and an appreciation of, mathematics.

From 1944 to 1957 he was a teacher at the Gymnasium in Holte, today a suburb of Copenhagen, but from 1949 he was himself also training other teachers at the Copenhagen State College of Education. The year 1958 brought a decisive change to his life: commissioned by UNESCO, he taught as a professor of mathematics at an African university, in Monrovia/Liberia, until 1960, and experienced the challenges from other cultural contexts. Upon his return, from 1961 on, he was called to the Royal Danish School of Educational Studies (Danmarks Lærerhøjskole), as a professor of mathematics and mathematics education. He remained in this position until his retirement in 1991.

As Mogens Niss wrote in his obituary of 1996:

"Bent was a legend in mathematics education in Denmark and the Nordic countries. His impact on the development of the teaching and learning of mathematics in primary and lower secondary education can hardly be over-estimated. He wrote textbooks and books on mathematics education, especially the very influential 'Goals and means in basic mathematics education' ('Mål og midler I den elementære matematikundervisning', 1967). He gave innumerable in-service courses and invited lectures at meetings and conferences. Naturally, he also served on hosts of national committees, including the Danish National Sub-Commission of ICMI (1961-1972). All this earned him a reputation as a charismatic, enthusiastic and extremely energetic mentor for generations of mathematics teachers, teacher trainers and colleagues."During the 1970s, Bent Christiansen developed from a teacher trainer and a curriculum specialist to a didactician of mathematics who took a serious interest in all aspects of mathematics education.

The focus of his development and research activities was at first the elaboration and practical experimentation of a great number of teaching materials and textbooks for students and also for teacher training and in-service training. A first such work was on combinatorics and probability for teachers, followed by an axiomatic development of geometry and a textbook 'Mathematics 65', for teachers.

Since the late 1950s, Christiansen came into ever closer contact with international developments for a modernisation of mathematics instruction. It was firstly through his participation at the seminars for mathematics teachers at Arlon, Belgium, organized by the Centre Belge de Pédagogie de la Mathématique and Georges Papy and Willy Servais, and later on at meetings of the CIEAEM and at regional conferences of ICMI, that he became acquainted with the innovators and their ideas. A telling experience was his participation at a regional ICMI conference in Aarhus in 1960 on "Modern Teaching of Geometry" where Dieudonné repeated in a more provocative manner his approach "Euclid must go!", but which was sharply criticised by Hans Freudenthal then. The outbreak of this bitter controversy about the goals for reforms was shocking for most of the participants.

Christiansen engaged actively in modernising mathematics teaching not only in Denmark, but also in the Nordic countries. He became a key member of the Nordic Committee for the modernisation of mathematics education, 1960-1967. While being an active propagator of the so-called New Mathematics, he later on defended it against thoughtless misinterpreters.

Since the late 1960s, Christiansen reactivated his relations with UNESCO. In October 1968, he organised a working group within the International Seminar on In-service Training of Mathematics Teachers, which took place at the UNESCO Institute for Education in Hamburg; in March 1969 he gave a paper at the meeting in Cairo initiating the "UNESCO Mathematics Project for the Arab States" and continued to be involved in this project. Eventually, in 1972, he became the programme specialist for mathematics of UNESCO - at a time, when UNESCO was a force in education and contributed considerably to promote mathematics education. Particularly memorable initiatives in this period, until 1974 - on leave from Copenhagen during this time -, were the Conference on Language and Mathematics, a topic of crucial interest to developing countries (Nairobi 1974) und UNESCO's series New Trends in School Mathematics, in particular its volume 4 (1979) giving key results of ICME 3 at Karlsruhe. His special concern was to promote mathematics teaching in the developing countries.

After the period of work for UNESCO, Christiansen joined the Executive Committee of ICMI in 1975 and was re-elected two times so that he served there for twelve years, until 1986. His particular merit is the preparation and organisation of ICME 3 in 1976, together with Hans-Georg Steiner. As a member of the IPC he prepared ICME 4 (Berkeley) and ICME 5 (Adelaide), too. Beside the international congresses, he was enormously active in preparing and organising regional and thematic ICMI seminars and congresses. Two initiatives in launching new directions in research into mathematics education should be mentioned in particular: Starting from ICME 4, an international working group "Systematic Cooperation between Theory and Practice in Mathematics Education" (SCTP), co-chaired by him, and gathering active members like Piet Verstappen, Guy Brousseau, Tom Cooney, Alan Bell, Leonie Burton, John Mason, Anna Sierpinska, Luciana Bazzini, Erich Wittmann, Heinz Steinbring, Falk Seeger, developed important contributions. The other is the BACOMET group, initiated in 1978 by Bent Christiansen, Geoffrey Howson and Michael Otte: Basic Components of Mathematics Education, elaborating well known research for improving teacher education.

B. CHRISTIANSEN 1964, Elementær kombinatorik og sandsynlighedsregning, Copenhagen, Munksgaard

B. CHRISTIANSEN, JONAS LICHTENBERG 1965, Matematik 65: en elementær lærebog, Copenhagen, Munksgaard

B. CHRISTIANSEN 1967, Mål og midler i den elementære matematikundervisning, Copenhagen, Munksgaard

B. CHRISTIANSEN 1962, Geometri for realafdelingen. Faglig tilrettelaeggelse og udarbejdelse af haefter, Copenhagen, DR, Danmarks Skoleradio/TV

B. CHRISTIANSEN et al. 1984, Mini-Conference at ICME 5: systematic co-operation between theory and practice in mathematics education: topic area research and teaching, Adelaide, Australia, August 25-29, 1984, Copenhagen, Royal Danish School of Educational Studies, Dept. of Mathematics

B. CHRISTIANSEN et al. (Eds.) 1986, Perspectives on mathematics education, Papers submitted by members of the Bacomet Group, Dordrecht, Reidel

GEOFFREY HOWSON, MOGENS NIss 1996, Obituary. Bent Christiansen 1921-1996, ICMI-Bulletin, 41, 21-24

HANS GEORG STEINER 1997, In Memoriam Bent Christiansen, ZDM, 29, 97-101

Author

Gert Schubring

Institut für Didaktik der Mathematik

Fakultät für Mathematik, Universität Bielefeld

gert.schubring@uni-bielefeld.de