Obituary: Ljubomir Davidov (19471998)
Friends of Ljubomir Davidov (photographed above, right, in Pravets, 1994 with his compatriot Petar Kenderov) were saddened
to hear of his death on 7 February 1998. His funeral in Sofia on 10 February attracted about 1000 fellow mathematicians and friends.
This is his obituary, written by Jenny Sendova.
About Ljubo  Smiling Through Tears
What matters is how you live, not how long. ... Seneca
`Now here's a beautiful problem for you ...'  how often have we, Ljubomir Davidov's friends and colleagues, heard these
words from his mouth. So have his students, many of whom are Olympic champions of the past or the present. These words
spontaneously followed even the first declaration of his feelings, and his chosen one took that as the highest guarantee
of his sincerity.
Ljubo's keen sense for æsthetics was manifested in a particularly powerful way in the choosing of problems for training
mathematical talents  an audience which appreciates the apt setting of the problem and the elegance of the solution more than
any other. But he was also incredibly skilled at transmitting his enthusiasm for the beauty of mathematics to the less wellversed
in this art.
Fate so decreed that that the last thing he saw on the computer screen was the cover of this book. `Problems from the Putnam
Contest will reach the Bulgarian fans of mathematics at last', his smiling face seemed to say. The feeling of deep satisfaction
was perfectly natural, because into the preparation of this book Ljubomir Davidov had invested the zeal of a collector and a researcher,
the high professional skill of an expert in mathematical contests and a technological competence which is still rarely seen among the
practitioners of pure mathematics.
`Ljubo was such a perfect born gentleman. I have been wondering what his family background was', George Berzsényi, a
wellknown American mathematician, writes in his letter of condolence. This may also be of interest to the students, the
colleagues and the friends of the author of this book.
Ljubomir Davidov was born on 2 June 1947 in Sofia in the family of one of the capital city's most prominent lawyers, Ivan Davidov. His maternal grandfather was Georgi Manev, professor of physics and founder of the Chair of Theoretical Physics, at various times Minister of Education and Convener of the University of Sofia. He was the first to introduce his young grandson to the realms of mathematics and physics. His exceptional skill of a storyteller Ljubo probably inherited from his father.
Following his graduation in mathematics at the Department of Mathematics and Mechanics (subsequently Department of Mathematics and Computer Science, DMCS) of the Kliment Okhridski University of Sofia in 1970, Ljubomir Davidov takes up a job at the Institute for Mathematics and Mechanics. In 1978 he defends a doctoral thesis in mathematics in the Moldavian Academy of Sciences. In 1986 he receives an associate professorship in algebra at the DMCS, where he works until 1990. Since then he is an associate professor at the Department of Education in Mathematics and Computer Science at the Institute for Mathematics and Computer Science (IMCS), Bulgarian Academy of Sciences. As an acknowledgement of his great organising skills, he is elected President of the Union of Bulgarian Mathematicians (19921993) and Deputy Director of the IMCS (1997).
His scientific interests are mainly in algebra, more specifically in the structural theory of associative rings and algebras.
In 1980 he becomes actively involved in the problems of teaching mathematics in the high school.
Though a wizard with a chalk in front of a blackboard, Ljubo was enthusiastic about exploring the potential of the new information technologies for enriching maths classes. His broad interests and knowledge made him an indispensable adviser in all manner of thorny situations  from solving a problem from a contest or competition to taming a new piece of software or elucidating the theory of electoral systems and mechanisms. His activity in the development of teaching materials and methods for integrating information technologies in the teaching of mathematics earned wide international recognition. In 1989 Ljubomir Davidov was invited to lecture at the University of California for a month, and in 1990 he was a Fullbright Professor at the Stevens Institute of Technology in New Jersey, USA.
From 1989 to 1993 Ljubomir Davidov was the leader of the Bulgarian team at international Olympiads in mathematics and contributed significantly to their success. Let it be reminded that the Bulgarian team led by him won the third place (after China and Germany), with 2 gold and 4 silver medals, at the International Mathematical Olympiad in Turkey, 1993. His prestige as a person with a great part in the formation of the traditions of mathematical contests was further strengthened at the Second International Conference of the World Federation of National Mathematics Competitions (Pravetz, 1994), where he was one of the principal organisers. During the Eighth World Congress of Mathematical Education (ICME'8, Sevilla 1996) Ljubomir Davidov was elected regional representative of the WFNMC for Europe. At the most recent instalment of the International Mathematical Olympiad (Argentina, 1997) he was invited by the organisers to supervise the coordination.
With his works (over 40 scholarly publications and 25 books), his brilliant lectures in linear algebra and higher algebra, his course of contemporary school algebra and the electives he read at the University of Sofia, the Burgas Free University and the New Bulgarian University, Ljubomir Davidov made a lasting mark in Bulgarian mathematics and ignited hundreds of yound minds with his admiration of the beauty of this science.
His dedication, his deep perception of problems, gift for organising, analytical mind, personal refinement and sense of humour
fill our hearts with gratitude for the time spent with him. ...
Ljubomir Davidov's cause, and his name with it, will have the recognition of all lovers of mathematics young and old.
Jenny Sendova
