Preface This brochure gives a concise presentation of the past and the present of the Alfréd Rényi Institute of Mathematics, birthplace of many important scientific discoveries and venue of numerous high-level meetings of mathematics. Besides an overview of the activities and the history of the institute, you will find here information on our current members as well as some former members and regular visitors whom we are proud of. A first version of this text was compiled in 2000, on the occasion of the 50th anniversary of the Institute. The present revised and updated version contains a lot of additional information and we hope that it gives a faithful picture of the Institute at the dawn of the third millenium. 1 A brief chronology of the Institute 1950 Founding of the Institute, under the name Institute for Applied Mathematics of the Hungarian Academy of Sciences. Alfréd Rényi, aged 29 at the time, is appointed as the first director. 1955 The name of the Institute is changed: it becomes the Mathematical Institute of the Hungarian Academy of Sciences. 1958 The institute moves to its current premises. 1970 Death of Alfréd Rényi. László Fejes Tóth is the new director. 1983 László Fejes Tóth is followed by András Hajnal in the director’s chair. 1984 Paul Erdős, member of the Institute, receives the Wolf Prize in Mathematics. 1992 Domokos Szász is appointed as the new director of the Institute. 1996 Gyula Katona becomes director of the Institute. Members of the institute take an active part in the organization of the Second European Congress of Mathematics, held in Budapest. 1999 The Institute takes up the name of its founder Alfréd Rényi. 2000 The Institute receives the grant “Centre of Excellence” from the European Union. 2001 A new extension of the building of the institute is inaugurated, giving rise to a great improvement in working conditions. A joint graduate program is launched, in cooperation with Central European University. For a more detailed history, see the corresponding chapter in the second half of this brochure. 2 Alfréd Rényi (1921-1970) Born and educated in Budapest, he became a student of Lipót Fejér, and wrote his dissertation in 1945 under the supervision of Frigyes Riesz. In 1946 he went to Leningrad (now Saint Petersburg) where Yu. V. Linnik and I. M. Vinogradov were his advisors. His solution of the so-called quasi-Goldbach conjecture in his 1947 thesis attracted considerable attention. Partially due to this result, he became a corresponding member of the Hungarian Academy of Sciences in 1949. He received an associate professorship at the Loránd Eötvös University of Budapest in 1947, and a full professorship in Debrecen in 1949. In 1950 he was appointed as director of the Applied Mathematical Institute of the Hungarian Academy of Sciences. From 1952 on he was also chair of the department of probability Theory at Loránd Eötvös University. He kept both positions until his death in 1970. He took Alfréd Rényi part in public life with amazing energy: he was a member of the editorial board of several journals and secretary general of the János Bolyai Mathematical Society. As director, he provided shelter at the Institute for various prominent scientists who were persecuted after the 1956 revolution. In his scientific work he made notable contributions to several branches of mathematics. Some of his most important results concern probabilistic methods in number theory (including a breakthrough in Goldbach problems), the development of the theory of random graphs (jointly with Paul Erdős), and the introduction of the socalled Rényi-entropy. The famous Hungarian school in statistics grew out from his work. His textbook on probability theory, first published in German and then translated into several Alfréd Rényi languages, has been in widespread use. Aside of his theoretical work, he published regularly on popular mathematics, and encouraged applications of mathematics. He was chair or co-chair of 3 numerous mathematical conferences, and was visiting professor at various universities around the world. Through his students, his spirit is still alive today. For his contribution to the axiomatization and application of probability theory he received the Kossuth Prize (the highest scientific prize awarded by the government) twice: in 1949 and in 1954. In 1956 he became a full member of the Hungarian Academy of Sciences. Two years after his untimely death in 1970, the Institute founded a prize in his memory; since 1999 it also bears his name. Research at the Institute Currently, researchers at the institute work in 10 research divisions, and some of them also in smaller research groups focused on more special subjects. The 10 current research divisions are: ♦ ♦ ♦ ♦ ♦ ♦ ♦ ♦ ♦ ♦ Algebra Algebraic Geometry and Differential Topology Algebraic Logic Analysis Combinatorics and Discrete Mathematics Convex and Discrete Geometry Information Theory Number theory Probability Theory and Mathematical Statistics Set Theory and Set-theoretic Topology In addition, research groups on cryptology, database theory, mathematical immunology and statistical physics are also active at the Institute. Let us now briefly review the history and activities of the various research groups. The school in combinatorics is the first to be mentioned. As the result of the work of Paul Erdős, Tibor Gallai, András Hajnal, Alfréd Rényi, Pál Turán, Vera T. Sós and their students, the Institute (in close collaboration with Eötvös University) has become one of the world centers in combinatorics. Here is the birthplace of the theory of random graphs, of the so-called probabilistic method in combinatorics, of basic results about extremal graphs and extremal set systems, or the regularity lemma describing the structure of huge graphs. Our researchers have achieved breakthrough results concerning discrepancy, combinatorial methods in group theory, and in combinatorial applications of entropy and graph entropy. Among the combinatorial 4 applications of theoretical computer science, important results have been achieved in search theory, in the complexity of combinatorial algorithms, in cryptology and in the combinatorial theory of databases (in cooperation with the Computer and Automation Research Institute of the Hungarian Academy of Sciences). From the very beginning, number theory has also been one of the most ardently cultivated areas of research at the Institute. A significant analytic and additive number theoretic school was formed under the leadership of Pál Turán, in close collaboration with researchers from Loránd Eötvös University. Basic results about the Riemann hypothesis, the distribution of prime numbers, multiplicative functions, dense sequences and probabilistic constructions of number theory have been achieved by Gábor Halász, András Sárközy, Endre Szemerédi, Imre Ruzsa and their collaborators. The analysis group was founded by Béla Szőkefalvi-Nagy, the famous functional analyst. Following the footsteps of Lipót Fejér, Gábor Szegő, Pál Erdős, Pál Turán and Géza Freud, research in approximation theory and the theory of orthogonal polynomials has been the main focus of analysts at the Institute. They initiated lacunary interpolation within interpolation theory, an area still active today. More recently, rational approximation and weighted approximation have also been the object of thorough study. Research in set theory and in mathematical logic has also been successful and highly acclaimed. Outstanding results have been achieved in combinatorial set theory, culminating in a monograph about the theory of partitions coauthored by András Hajnal, former director of the Institute and later director of DIMACS in New Jersey, Paul Erdős, and Richard Rado. Presently, settheoretic topology and mathematical logic also have active groups at the Institute. During the last decades, Budapest has Handwritten notes by Paul Erdős become an important center for algebraic logic as well. This school continues related work by Alfred Tarski exploring a flourishing connection between cylindric algebras and logic. 5 Discrete geometry has become an independent discipline in mathematics as a consequence of the work of László Fejes Tóth, another former director of the Institute. Hungarian researchers have played an essential role in this process. The discrete geometry group of the Institute, together with researchers from Loránd Eötvös University, achieved significant results in the field. Being the main area of research cultivated by Alfréd Rényi, the founder of the Institute, probability theory and mathematical statistics have always been present, with particular emphasis on applications. It was also Rényi who started to work on information theory in his last years. Later the Information Theory Division became famous under the leadership of Imre Csiszár. One of the most significant results here was the elaboration of multiuser information theory. The group’s work opened up new directions in the application of information theory, notably in statistics (maximal entropy), in probability theory (measure concentration, theory of large discrepancies), and in combinatorics (graph entropy, graph conductivity). The Algebra Division was formed about forty years ago by László Rédei. Its research profile initially focused on group and semigroup theory, lattices and universal algebra. This spectrum has gradually expanded with the introduction of category theory, linear algebra and ring theory. Presently a group working on asymptotic properties of groups is also very active at the Institute. Biometrics, the branch of statistics connected with medicine, has always played an important role in the life of the Institute. Outstanding advances connected with genetics and recognition of cancer cells have resulted from statistical investigations conducted by Gábor Tusnády. The founder of the Hungarian school in statistical physics is Domokos Szász. The Institute has been one of the centers of this field. The main areas investigated are the dynamic theory of Brownian motion, infinite differential equations, and the mathematical foundations of the Boltzmann hypothesis. In the latter area of investigation, work of researchers of the Institute has produced breakthrough results. The 1979 Kőszeg conference in this area was of essential importance; here researchers from the Soviet Union and from Western countries worked together on the topic for the first time. The group in algebraic geometry and differential topology is the youngest of the Institute. It came into existence in 1998 when young researchers having obtained their PhD from prestigious foreign universities launched a weekly seminar. Members of the group are working on a wide range of topics in the 6 forefront of current research but previously not cultivated in Hungary, including classification of algebraic varieties, singularity theory, the theory of motives or low-dimensional topology. Contributions to applications of mathematics The Institute was founded as a research centre for applied mathematics, and applications determined its main profile during the 1950’s. This included close collaboration with industrial partners. Over the decades, the Institute’s main focus shifted towards theoretical research, especially after the foundation of the Computer and Automation Research Institute of the Academy which took over several fields of research in applied mathematics from the Institute. Nevertheless, applications still play an important part in the Institute’s life. Results of our colleagues working in information theory and database theory are implemented in cryptography and computer science. Within statistics, preestimation of population size and other problems related to living organisms are among the most cultivated areas of application at the Institute. In the 1980’s the Institute’s help was essential for the revival of a profession forgotten in Hungary for over forty years: that of insurance mathematics. The Institute also took an active part in preparing the reform of the Hungarian pension system. In collaboration with the Hungarian Oncology Institute, our researchers have developed a computer program for recognizing cancerous cells. Another joint project, developed together with ASK Ltd., was a device for cutting curtains, presented at the 2000 World Exhibition in Hannover. Among ongoing collaborations, the most important one is a joint project in cryptography together with Hewlett Packard Hungary, aiming at the elaboration of “digital watermarking”. With the evolution of industrial applications in Hungary, it is expected that there will be a growing demand for theoretical mathematics and its applications. The Institute is ready for the challenge. Scientific meetings at the Institute Most of our research divisions run a weekly seminar for specialists in the field during the academic year. These have met at the same hour for decades now and form part of the Institute’s tradition; for instance, everyone knows that Thursday afternoon is for combinatorics, or Monday morning is for algebra. 7 About once a month, always on a Monday afternoon, a colloquium lecture is organized for all members of the Institute and for interested visitors. The aim of these lectures is to present significant results of researchers of the Institute to a wider audience, and also to give an opportunity for prominent researchers from Hungary and abroad to speak about less specialized topics. Every two years, the Institute organizes jointly with the János Bolyai Mathematical Society the Pál Turán Memorial Lectures. This is usually a series of three lectures given by a famous expert active in one of the research areas of the late Pál Turán: number theory, analysis or combinatorics. Recent Turán lecturers include Hugh Montgomery, Peter Lax and Peter Sarnak. Since the 1960’s, the Institute has been hosting and organizing international conferences ranging from 2-day workshops devoted to a specialized topic to large conferences with hundreds of participants. During recent years, the largest meetings organized by members of the Institute were the 2nd European Congress of Mathematics in 1996, whose organizing committee was chaired by the director of the Institute, the 1999 conference on ‘Paul Erdős and His Mathematics’, which had 450 participants from all over the world, and the 2001 Euroconference on ‘Finite and Infinite Combinatorics’. In September 2001, the Institute hosted a 3-week summer school and workshop in algebraic geometry devoted to ‘Higher Dimensional Varieties and Rational Points’ which received an important European subvention, and in 2003 the Von Neumann Centennial Conference on linear operators and the foundation of quantum mechanics, co-organized by the Bolyai Society and the American Mathematical Society. In June 2004, a 3-week workshop in low-dimensional topology will take place at the Institute, organized jointly with the Clay Mathematical Institute. Apart from these large events, the Institute regularly hosts a number of international conferences and workshops for smaller groups of specialists, which since 1998 are grouped in a Turán Workshop Series in mathematics. The webpage http://www.renyi.hu/old-conferences.html contains a list of meetings organized at the Institute since 1999. Visitors at the Institute A part of the Institute’s activity which has been receiving increasing importance during recent years is the hosting of visitors from Hungary and abroad. 8 Each year, the Institute offers visiting positions for mathematicians working at Hungarian universities, usually for a duration of 6 or 12 months, providing them ideal conditions for conducting undisturbed research. In such a way, the Institute has had a part in the achievement of several breakthroughs: for instance, Miklós Laczkovich of Eötvös University proved Tarski’s conjecture on the ‘squaring of the circle’ while a visiting researcher at the Institute. The Institute has been receiving foreign scientists for short stays for decades now, many of them regular visitors and close collaborators of our researchers. During recent years, the number of foreign visitors plummeted and the Institute can now host visitors for longer stays as well. Instrumental in this change was the Centre of Excellence grant of the European Union, allotted to the Institute between 2001 and 2003, which made possible the invitation of 33 scholars and post-docs for visits ranging from one month to a whole year. This grant also contributed to the funding of 13 international conferences organized during this period. Another institution enabling the invitation of visitors and the organization of workshops is the Paul Erdős Mathematical Summer Institute, founded, jointly with the János Bolyai Mathematical Society and several universities, in 1997. It is co-financed by the Hungarian Ministry of Education, the Hungarian Academy of Sciences, Rutgers University (US), Microsoft Research (US), and Lucent Technologies (US). During the coming years, the Institute wishes to develop its international contacts further, with the aim of becoming not only an important European centre but also a well-known meeting place for mathematical research. Scientific and postgraduate education in the Institute During the first decades of the Institute’s existence, most of its researchers held part-time positions at various Hungarian universities and vice versa, a number of distinguished university professors were also part-time members of the Institute. This resulted in a close collaboration with the educational system and enabled to draw many talented young students towards mathematical research. Nowadays our relation with undergraduate education is less tight. We do not offer part-time positions any more for university teachers, but we regularly host them as visiting researchers. Similarly, only a few members of the Institute hold part-time university positions, though many of them still teach undergraduate and graduate courses at various universities – mostly at Eötvös University and at the Technical University of Budapest, but also in Debrecen. 9 On the other hand, the Institute takes a more and more active part in graduate and post-graduate education. Our researchers usually serve as advisors to 1012 graduate students from universities in Budapest. From the academic year 2001/2002, a joint international graduate program has been launched together with Central European University, open to all countries of the world. The teaching language is English and the educational system is the one currently adopted in the US; correspondingly, the PhD titles awarded will be accepted in the US as well. Our researchers serve both as supervisors and instructors in the program. Within the framework of a program coordinated by the Hungarian Academy of Sciences, the Institute hosts each year 10-15 young researchers with a oneyear contract, which is renewable twice. These are recent PhD’s or graduate students about to finish their thesis, whose scientific work is supervised by a researcher at the Institute. After the end of their contract, several young researchers have received offers for a position at the Institute, some even tenured ones. The Institute also regularly hosts post-doctoral students from abroad whose number is steadily increasing thanks to the availability of various intraEuropean and international fellowships. We have joined or are planning to join various European research training networks which will help to develop further the international training activities of the Institute. Researchers currently working at the Institute This section gives a brief presentation of our current members; it is followed by lists of our honorary members and some prominent former members. All researchers below have a PhD or equivalent title. The ‘Doctor of Science’ title is awarded by the Academy to researchers with a substantial research experience and achievement; it roughly corresponds to that of a full professor. Among the prizes mentioned, the Széchenyi Prize (formerly State Award, or Kossuth Prize) is the highest distinction of the Hungarian Republic awarded to scientists; the Academy Award and the Mathematical Award are awarded by the Academy for outstanding research achievements. Several of our researchers are members or corresponding members of the Hungarian Academy of Sciences. 10 Hajnal Andréka (b. 1947, at the Institute since 1977) Doctor of Science (1993). Her main areas of interest include logic, algebraic logic, theoretical computer science, and relativity theory. She proved (jointly with Hodkinson and Németi) that every finite relativized relation algebra is representable over a finite base. She is a member of the Council of the Association of Symbolic Logic. Pham Ngoc Ánh (b. 1956, at the Institute since 1988) Doctor of Science (1988). His main area of interest is ring and module theory. Probably his most famous result states that a commutative rings admits Morita duality if and only if it is linearly compact. András Ádám (b. 1934, at the Institute since 1957) Doctor of Science (1986) He is interested in Boolean functions, graph theory and algebraic automata theory. He has written two books. László Babai (b. 1950, at the Institute since 1997) Member of the Academy, Mathematical Award (1983) Plenary lecturer of the 1992 European Congress of Mathematics. He contributed to the theory of graph automorphisms and of permutation groups, in particular concerning the number of elements in primitive permutation groups. His other important field is complexity theory, where his theorem about transparent proofs is of basic importance. Currently on leave from the Institute, he is a professor at the University of Chicago. Antal Balog (b. 1956, at the Institute since 1983) Doctor of Science (2000), Mathematical Award (1992), Academy Award (1995) His field is number theory, especially the distribution of prime numbers. A well-known expert in sieve methods and exponential sums, his most striking result is that there are infinitely many "magic" triangles, tetrahedrons, etc. in primes. 11 Imre Bárány (b. 1947, at the Institute since 1978) Doctor of Science (1993), Erdős Prize (1995), Academy Award (1998) Invited speaker at the International Congress of Mathematicians, Beijing, 2002. His main areas of interest are discrete and convex geometry, with applications in operation research and computer science. He has obtained fundamental results about the asymptotic shape of certain random objects. István Berkes (b. 1947, at the Institute since 1971) Doctor of Science (1996), Academy Award (2003). His main field of interest is probability theory and its applications in analysis, in particular for orthogonal and lacunary series. András Bezdek (b. 1956, at the Institute since 1983) His fields of interest are discrete and combinatorial geometry and convexity. Many of his results concern packing and covering problems in 2- and 3dimensional Euclidean space. András Biró (b. 1971, at the Institute since 1997) He works in various areas on number theory, including the analytic theory of automorphic functions, Turán’s theory of power sums and diophantine approximation. He recently solved problems of Yokoi and Chowla concerning quadratic fields of class number one. Péter Bod (b. 1924, at the Institute since 1959; deputy director, 1985–1995; retired in 2003). Doctor of Science (1973). His main fields of interest are operation research and actuarial problems in social security. He has achieved results in multiobjective linear programming, in the characterization of convex sets having a least element, in the non-linear generalization of input-output models and in the mathematical modeling of large-scale systems. He currently serves as Advisor to the Director. 12 János Bognár (b. 1932, at the Institute from 1960, retired in 1995) A specialist in functional analysis, he has written a monograph on Indefinite inner product spaces (volume 78 of the prestigious Ergebnisse series of Springer-Verlag). Károly Böröczky, Jr. (b. 1964, at the Institute since 1992; scientific secretary, 1996–2000) His main fields of interest are discrete and combinatorial geometry as well as the theory of toric varieties. His monograph on Finite packing and covering will be published soon by Cambridge University Press. Organizer of several important international meetings in algebraic geometry and topology. Endre Csáki (b. 1935, at the Institute since 1959) Doctor of Science (1989). He is interested in limit theorems of probability and statistics and in combinatorial methods for random walk problems. He gave rates of convergence in Strassen’s theorem, thereby establishing a connection between Chung’s and Strassen’s laws of the iterated logarithm. Imre Csiszár (b. 1938, at the Institute since 1961) Member of the Academy, IEEE Shannon Award (1997), Academy Award (1988). He is the leader of the Hungarian school in information theory. His main work is the book “Information Theory” written jointly with János Körner. The book was the first overview of multiuser information theory. Ervin Deák (b. 1929, at the Institute from 1964; retired in 1995) At first his area of research was general topology, regarding in particular various notions of dimension, later his interest switched to questions of mathematical education. Mátyás Domokos (b. 1968, at the Institute since 1995) A specialist in ring theory, he first worked on polynomial identities, then his research shifted to invariant theory and its connections with representations and quantum groups. 13 Gábor Elek (b. 1963, at the Institute since 1996) His work concentrates on the interface between functional analysis on manifolds, algebra and combinatorics; his main interest is in amenable groups, topological entropy and l_p-cohomologies. Miklós Erdélyi Szabó (b. 1962, at the Institute since 2002) He is interested in set theory, topological models as well as in artificial intelligence; he is also the head of our Computer Department. Péter L. Erdős (b. 1956, at the Institute since 19??) He works in extremal graph theory and the application of graphs to problems in mathematical biology. Gábor Fejes Tóth (b. 1947, at the Institute since 1974), Doctor of Science (1996). Working in discrete geometry, he is a worldwide recognized authority on packing and covering problems. His survey papers are the standard references about the field. Organizer of prestigious international meetings in discrete geometry (including Oberwolfach seminars). Zoltán Füredi (b. 1954, at the Institute since 1978) Doctor of Science (1989), Academy Award (1989). Invited lecturer at the 1994 International Congress of Mathematicians. He has achieved ourstanding results in extremal set theory, graph theory and discrete geometry, including the solution (together with P. Frankl) of a famous problem of Littlewood and Offord. János Gerlits (b. 1945, at the Institute since 1968) His field of research is general and set-theoretic topology. In particular, he has important results on function spaces and on cardinal functions of dyadic spaces. Ervin Győri (b. 1954, at the Institute since 1977; deputy director since 1997) Doctor of Science (1994). His main fields of interest are combinatorics and graph theory. His major results are a minimax theorem on intervals, a partition characterization of k-connected graphs (proved independently by L. Lovász as well) and solutions to several problems of Erdős in extremal graph theory. 14 István Juhász (b. 1943, at the Institute since 1975) Doctor of Science (1977), Mathematical Award (1977), Academy Award (1997) His main areas of interest are set theory and general topology. Together with A. Hajnal he has created an internationally recognized school in set-theoretic topology. He is the author of two monographs: Cardinal functions in topology and Cardinal functions - ten years later. Gyula Katona (b. 1941, at the Institute since 1966; Director since 1996) Member of the Academy, Academy Award (1989). An internationally recognized expert in combinatorics, he has achieved important results in extremal set theory and concerning the combinatorial structure of databases. He also pays great attention to educating future scientists: several of his students are leading mathematicians today. His organizing work is also of great importance. András Kroó (b. 1954, at the Institute since 1976) Doctor of Science (1988), Academy Award (2002). His main area of interest is Approximation Theory. His best known result concerns the differentiability of the operator of best approximation in the space of continuous functions. Antónia L. Földes (b. 1945, at the Institute since 1969) An expert in probability theory, she is mainly interested in questions of local time, random walks and Wiener processes. Currently on leave from the Institute. Anna Lee (b. 1928, at the Institute from 1971; retired since 1993) A researcher in algebra, her field of interest is matrix theory. She has investigated involutions of the complete matrix ring over the complex numbers. Judit Madarász (b. 19??, at the Institute since 2001) She works in algebraic logic and the logical foundations of relativity theory. 15 Zoltán Magyar (b. 1959, at the Institute since 1987) His main field of research is the analytic theory of Lie groups and their representations. Author of two monographs: one on Continuous Linear Representations, the other on The Lebesgue Integral. Péter Major (b. 1947, at the Institute since 1971) Doctor of Science (1989), Academy Award (1984) He is interested in probability theory and statistical physics. His best known result is a joint work with János Komlós and Gábor Tusnády about the approximation of identically distributed random variables by a Wiener process. This construction is often called the KMT theory or the Hungarian method in the literature. Endre Makai, Jr. (b. 1947, at the Institute since 1970) Doctor of Science (1996), Academy Award (1998). He has a double research interest: he works in convex and discrete geometry and also in general topology. He has obtained important results by combining geometrical and purely topological methods. László Márki (b. 1947, at the Institute since 1970) Doctor of Science (1996) His main area of interest is algebra: semigroups, rings, universal algebra, categories. He has recently introduced the notion of semi-abelian categories (with Janelidze and Tholen) which answers an old question of MacLane. He served as Vice-President of the European Mathematical Society from 1993-1996. Katalin Marton (b. 1941, at the Institute since 1974) Doctor of Science (1999). After working on problems in information theory and some related problems in combinatorics and ergodic theory, her current recent interest is mainly in measure concentration. 16 József Merza (b. 1932, at the Institute from 1967, retired since 1993) His research interest was in classical differential geometry. He served as managing editor of the Institute’s proceedings Studia Scientiarium Mathematicarum Hungarica for decades and also as head of the library, where he is still active today. Dezső Miklós (1957, at the Institute since 1982, deputy director since 1996). His main areas of research are combinatorics (extremal set theory, algebraic combinatorics) and the combinatorial structure of databases. A very active organizer, editor of several volumes. Zsigmond Nagy (b. 1950, at the Institute since 1975) He has achieved significant results in general and settheoretic topology, in particular concerning the theory of function spaces. Tibor Nemetz (b. 1941, at the Institute since 1969) Doctor of Science (1996) His research interests include combinatorics, information theory, statistics as well as didactics. He is one of the initiators in Hungary of research in cryptology and its practical applications. He is especially interested in the estimation of the entropy of written languages. András Némethi (b. 1959, at the Institute since 2004) Doctor of Science (2001) A well-known expert on singularities of complex algebraic varieties. Continuing the program initiated by M. Artin and Laufer, he has obtained deep results in the classification of normal surface singularities by studying both algebro-geometric and topological invariants. 17 István Németi (b. 1942, at the Institute since 1976) Doctor of Science (1987) His main areas of interest are logic, algebraic logic, theoretical computer science, and relativity theory. He has obtained fundamental results about cylindric algebras and relation algebras, solved several famous problems raised by Tarski and created a school in algebraic logic at the Institute. Author of the monograph Cylindic set algebras (jointly with Andréka, Henkin, Monk and Tarski). János Pach (b. 1954, at the Institute since 1977) Doctor of Science (1996), Academy Award (1998) His main fields of interest are discrete and computational geometry, convexity and combinatorics. He is a recognized expert in geometric graph theory and author of the influential book Combinatorial Geometry (jointly with Pankaj Agarwal). Besides being a prolific researcher, he has a number of students around the world. Apart from his position at the Institute, he is also a professor at the Courant Institute, New York. Dénes Petz (b. 1953, at the Institute between 1982 and 1992 and from 2004) Doctor of Science (1989) His fields of research are functional analysis and the mathematical foundations of quantum theory. Author of two monographs: Quantum Entropy and its Use (with M. Ohya, Springer, 1993) and The Semicircle Law, Free Random Variables and Entropy (with F. Hiai, AMS, 2000). János Pintz (b. 1950, at the Institute since 1977) Doctor of Science (1984). An internationally recognized expert in analytic number theory, he has achieved important results concerning the distribution of prime numbers and the Goldbach conjectures. László Pyber (b. 1960, at the Institute since 1987) Doctor of Science (1998), Erdős Prize (1996). Invited speaker of the 1996 Mathematics. His main interest theory. He has determined the number of n-element groups. European Congress of lies in asymptotic group asymptotic value of the Recently, he has been 18 successful in studying residual properties of groups and the subgroup growth problem (jointly with Lubotzky, Shalev and others). Lídia Rejtő (b. 1946, at the Institute since 1969) Her research interest is in mathematical statistics and limit theorems in probability theory. Currently on leave from the Institute. Szilárd Révész (b. 1958, at the Institute since 1990) He began his mathematical research by investigating problems related to the distribution of prime numbers. Later, his interest shifted to approximation theory, in particular inequalities and extremal problems. Imre Z. Ruzsa (b. 1953, at the Institute since 1976) Corresponding member of the Academy, Academy Award (1995), Erdős Prize (1989). He is a leading expert in additive number theory and has basic results in applying probabilistic methods in number theory. Together with Gábor Székely, he has also developed a semigroup theoretic method in proving limit theorems for probability distributions. Ildikó Sain (b. 1951, at the Institute since 1982) Her main research interest lies in model theory, algebraic logic and universal algebra. Recently, she has been interested in finitizable algebraization of first-order logic. Attila Sali (b. 1959, at the Institute since 1984) He has been working in several areas of combinatorics, including extremal and algebraic combinatorics, database theory and graph theory. Miklós Simonovits (b. 1943, at the Institute since 1986) Corresponding member of the Academy, Academy Award (1993). His main areas of interest are combinatorics and graph theory. He is one of the pioneers of extremal graph theory, an area where he is still very active today. Together with L. Lovász, he has obtained fundamental results concerning the algorithmic complexity of computing the volume of a convex body in Euclidean space. 19 Gábor Simonyi (b. 1963, at the Institute since 1989) His main research activity blends information theory and graph theory; in particular, he is an expert on graph entropy. Lajos Soukup (b. 1958, at the Institute since 1986) His main field of interest is set theory, in particular independence results in set-theoretic topology. His work with S. Shelah in set theory and the theory of Boolean algebras is also widely known. András Stipsicz (b. 1966, at the Institute since 2002) He is a well-known expert in symplectic topology, with a main focus on 4manifolds. Together with R. Gompf, he wrote the important advanced textbook 4-Manifolds and Kirby Calculus (AMS, 2000). József Szabados (b. 1938, at the Institute since 1968) Doctor of Science, Academy Award (1982). His field of interest is approximation theory; in particular interpolation and weighted polynomial approximation in various spaces. He wrote the monograph Interpolation of Functions (jointly with P. Vértesi). He has been managing and editing the journal Acta Mathematica Hungarica since 1962. Endre Szabó (b. 1964, at the Institute since 1996) His main interest is in algebraic geometry, where he has achieved significant results concerning rationally connected varieties and automorphism groups of varieties. Tamás Szamuely (b. 1971, at the Institute since 1998; scientific secretary, 2001–2004) He is interested in wide-ranging topics in algebraic and arithmetic geometry, including algebraic cycles, motives, fundamental groups and geometric aspects of class field theory. Speaker at the Bourbaki Seminar in June 2003. 20 Domokos Szász (b. 1941, at the Institute since 1971; Director, 1993–1995), Member of the Academy, Academy Award (1984). Though he began his career as a probability theorist, he is best known as the founder of the internationally renowned Hungarian statistical physics school. Starting from equilibrium statistical physics, he turned to the theory of billiards, and in particular the Boltzmann ergodic hypothesis. Together with Ya. G. Sinai, he achieved the first breakthrough in the mathematical foundation of the hypothesis. Endre Szemerédi (b. 1940, at the Institute since 1965) Member of the Academy, Academy Award (1979), Erdős Prize (1977). His profound results in number theory and combinatorics are widely used and have a significant impact on research. He showed that any sequence of integers with positive density contains arithmetical progressions of arbitrary length, thereby solving a famous problem of Erdős and Turán. His most influential result in combinatorics is the so-called regularity lemma. Gábor Székely J. (b. 1947, at the Institute since ???) Doctor of Science (1986) His main areas of interest are algebraic probability theory and nonparametric statistical tests. He is the author of Paradoxes in probability theory and mathematical statistics (1986) as well as Algebraic probability theory (with Imre Z. Ruzsa, 1988). He is currently on leave from the Institute. Ágnes Szilárd (b. 19??, at the Institute since 2003; scientific secretary from 2004) She is interested in computing invariants for singularities of complex algebraic varieties. 21 Gábor Tardos (b. 1964, at the Institute since ???) Prize of the First European Congress of Mathematics, Erdős Prize (1999). Invited speaker at the Second European Congress of Mathematics. His main areas are complexity theory and combinatorics. He has achieved profound results about first-order statements on random graphs and an important breakthrough towards the Hanna Neumann conjecture concerning subgroups of free groups. Vera T. Sós (b. 1930, at the Institute since 1987) Member of the Academy, Academy Award (1983), Foreign member of the Austrian Academy of Sciences, Széchenyi Award (1997) She is one of the founders of the Hungarian school in combinatorics. Her other main research area is number theory, especially diophantine approximation and uniform distribution. In combinatorics, she has achieved important results on pseudorandom structures and extremal problems. Géza Tóth (b. 1968, at the Institute since 2001) He has obtained significant results in discrete and combinatorial geometry, with a main focus on geometric aspects of Ramsey theory. Gábor Tusnády (b. 1941, at the Institute since 1965) Member of the Academy, Erdős Prize (1981). The basic goal of his work is building and investigating stochastic models. He has achieved significant results in statistical problems connected with genetics and cancer research and has created interdisciplinary research groups around his projects. Péter Vértesi (b. 1941, at the Institute since 1975) Doctor of Science (1982), Academy Award (2002) He works in approximation theory, especially interpolation theory. His most significant result is the almost everywhere divergence theorem of Lagrange interpolation (joint work with P. Erdős). Together with J. Szabados, he wrote the book Interpolation of Functions. 22 Richárd Wiegandt (b. 1932, at the Institute since 1964) Doctor of Science (1975). He works in algebra with a main interest in rings and radicals. He is one of the founders of general radical theory going beyond algebraic structures. 23 Honorary members of the Institute Miklós Ajtai (1946-) External member of the Academy His main fields of interest are theoretical computer science, mathematical logic and combinatorics. He has achieved several breakthroughs in the theory of randomized algorithms, mostly jointly with J. Komlós and E. Szemerédi. At the Institute between 1970 and 1985, he presently works at IBM Almaden Research Center. József Beck (1952-) Doctor of Science (1993) Invited speaker at the International Congress of Mathematicians (Berkeley, 1986). A leading expert on uniform distribution and discrepancy theory, he is the author of Irregularities of Distribution (with W. L. Chen, Cambridge University Press, 1987). Probably his best known result is his 1993 solution of an old conjecture on uniform distribution on the k-dimensional torus. He has also done important work in game theory. At the Institute between 1977 and 1984, he is currently Harold Martin Chair Professor at Rutgers University. Béla Bollobás (1943-) External member of the Academy A worldwide recognized expert in combinatorics. He is the author and editor of numerous books, including authoritative texts on Combinatorics, Modern Graph Theory and Random Graphs. A regular visitor to the Institute, he is currently a professor at the University of Memphis, Tennessee. László Csirmaz (1951-) His research interest is in logic and computer science. After a period at the Institute between 1975 and 1996, he is now head of the Computer and Statistics Center at Central European University. Miklós Csörgő (1932-) External member of the Academy He is interested in fine analytic path properties of stochastic processes, Wiener, empirical, local time and released processes. He is author and co-author of five books, among which Strong Approximations in Probability and Statistics, written jointly with Pál Révész, is a frequently cited fundamental work in the subject. He is currently a professor at Carleton University, Ottawa, Canada. 24 Péter Frankl (1953-) External member of the Academy His main field of interest is combinatorics. He has proven fundamental results in the theory of extremal hypergraphs. Excellent juggler, a TV personality in Japan. He worked at the Institute between 1976 and 1980 and is now at the University of Tokyo. József Fritz (1943-) Corresponding member of the Academy, Academy Award (1984) His main field of interest is mathematical physics. He has obtained fundamental results on differential equations with infinite degree of freedom (jointly with R. L. Robinson), and for infinite dimensional stochastic differential equations. He has students at various places around the world. After working at the Institute between 1967 and 1993, he is now a professor at the Technical University of Budapest. Kálmán Győry (1940-) Member of the Academy, Academy Award (1992), Széchenyi Prize (2002) He is the initiator in Hungary of the study of diophantine equations and the leader of the Debrecen number theory school. He has achieved important results in applying Baker’s method in transcendental number theory to finding effective bounds on the solutions of diophantine equations. He is a professor at the University of Debrecen, where he also served as Dean and Rector. András Hajnal (1931-) Member of the Academy, State Award (1970), Academy Award (1967); Director of the Institute (1983–1992). Invited speaker at the 1974 International Congress of Mathematicians. With Paul Erdős, Attila Máté and Richard Rado, he is the founder of combinatorial set theory and with P. Hamburger the author of a standard textbook on set theory. The Hungarian set theory school gained world fame under his leadership. He worked at the Institute between 1970 and 1992 and is currently a professor at Rutgers University where he also served as director of DIMACS. 25 Gábor Halász (1941-) Member of the Academy, Erdős Prize (1976) A prominent expert in analytic number theory, he has obtained fundamental results concerning mean values of multiplicative arithmetic functions. He has also worked in approximation theory and complex analysis and has an impressive list of students. After spending the period 19641986 at the Institute, he is now a professor at Eötvös University. János Horváth (1924-) External member of the Academy An expert in functional analysis and operator theory, he is the author of an influential 2-volume monograph on Topological Vector Spaces and Distributions. He is currently professor emeritus at the University of Maryland. Jerry L. Kazdan (19??-) Working on the interface of the theory of partial differential equations and differential geometry, he has obtained fundamental results (jointly with F. Warner) on the characterisation of curvature functions on 2-manifolds. He is a professor at the University of Pennsylvania and at Central European University. János Kollár (1956-) External member of the Academy Invited speaker at the 1990 International Congress of Mathematicians. Working mainly in algebraic geometry, he is a leading authority on the classification of higher dimensional varieties. Together with Miyaoka and Mori, he initiated the study of rationally connected varieties. He is the author of the important monographs Shafarevich Maps and Automorphic Forms (Princeton, 1995), Rational Curves on Algebraic Varieties (Springer, 1996) and Birational Geometry of Algebraic Varieties (with. S. Mori, Cambridge, 1998) and is editor of Inventiones Mathematicae. Currently he is a professor at Princeton University and a regular visitor to the Institute. János Komlós (1942-) External member of the Academy His areas of interest include probability theory, the theory of algorithms and graph theory. He is well known among others, for the "KMT embedding" in probability theory (joint work with Major and Tusnády), or for the AKS sorting network. At the Institute between 1967 and 2001, he is now a professor at Rutgers University. 26 János Körner (1946-) His main fields of interest are information theory and combinatorics. His book Information Theory written jointly with Imre Csiszár was the first overview of multiuser information theory. He has strongly contributed to combinatorical applications of information theory, in particular he introduced the concept of graph entropy. After a period at the Institute between 1970 and 1996, he is now a professor in Rome. Miklós Laczkovich (1948-) Member of the Academy, Academy Award (1991), Széchenyi Award (1998) His main research area is real analysis. Among other fundamental results, he has verified A. Tarski’s conjecture about "squaring the circle". He is a professor at Eötvös University and has been a visiting researcher at the Institute several times. László Lovász (1948-) Member of the Academy, State Award (1985), Wolf Prize (1999) He is one of the leading experts of the world in his major areas of research: combinatorics, graph theory and theoretical computer science. He has settled several famous questions in combinatorics like the Shannon capacity problem, the perfect graph conjecture, or the Kneser conjecture. His book Combinatorial Problems and Exercises is a standard text and reference in the field. Beyond his theoretical work he is a very active and productive organizer of the Hungarian and international mathematical community. He is a professor at Eötvös University and at Microsoft Research. Mihály Makkai (1939-) External member of the Academy A worldwide recognized, leading researcher in logic and the foundations of mathematics. He has made fundamental contributions to model theory and is one of the founders of categorical logic. He is a professor at McGill University, Montreal, Canada. 27 Péter Pál Pálfy (1955-; Deputy Director, 1991–1996) Doctor of Science (1997), Mathematical Award (1993) His research interests are in group theory and universal algebra. His most cited results include the classification of minimal algebras and the determination of finite groups with the general Cayley isomorphism property. After twenty years spent at the Institute from 1980, he is now a professor at Eötvös University. Pál Révész (1934-) Member of the Academy, State Prize (1978) He has obtained important results for local time, random walks and empirical processes in probability theory. Recently, he has also been interested in Wiener processes. Jointly with Miklós Csörgő, he wrote the fundamental book Strong Approximations in Probability and Statistics. After a period at the Institute between 1964 and 1985, he is now a professor emeritus at the Technical University of Vienna. András Sárközy (1941-) Corresponding member of the Academy, Academy Award (1992). His main areas of interest are additive and combinatorial number theory. Probably his most famous result is that the difference set of a dense sequence of integers always contains a perfect square. A researcher at the Institute between 1971 and 1994, he is now a professor at Eötvös University. Tamás Schmidt (1936-; Deputy director, 1971–1990) Doctor of Science (1969), His main area of research is lattice theory and universal algebra. His most celebrated result is a joint theorem with G. Grätzer stating that every algebraic lattice is isomorphic to the congruence lattice of an algebra. After a long stay at the Institute between 1958 and 1990, he is now a professor at the Technical University of Budapest. 28 Bálint Tóth (1955-) Doctor of Science (1999), Mathematical Award (1995), Academy Award (2003). Invited speaker at the third European Congress of Mathematics, 2000. His main areas of research are probability theory and stochastic processes. His major results are limit theorems for random walks with long memory exhibiting anomalous diffusion and the construction of the so-called `true self-repelling motion’, a stochastic process with striking analytic and phenomenological properties. After a period at the Institute between 1983 and 1998, he is now a professor at the Technical University of Budapest. 29 Some prominent former members of the Institute György Alexits (1899–1978) Member of the Academy, Kossuth Prize (1951), State Award (1970) He was mainly interested in real functions. His most important results are in the field of Fourier analysis and approximation theory. He was at the Institute between 1971 and 1974. László Alpár (1914–1991) Doctor of Science (1978) He worked in analysis. His main results deal with the behaviour of analytic functions on the circle of convergence. At the Institute between 1956 and 1984, he also served as Deputy Director. András Békéssy (1925-) Doctor of Science, Deputy director (1964–1971), Academy Award (1984) He is interested in applications of complex analysis, in combinatorics and in probability theory. He has worked for WHO, and has written a book about databases (together with János Demetrovics). He worked at the Institute between 1964 and 1971. Imre Bihari (1915–1999) Doctor of Science (1979) His main field of interest was differential equations. At the Institute between 1962 and 1985, he initiated the study of semi-linear differential equations. Ákos Császár (1924-) Member of the Academy, Kossuth Prize (1963) His main interests are in real analysis and in general topology; he is the author of comprehensive textbooks on both subjects. His most important result is the unification of different topological structures by introducing syntopogenous structures. Though never a full-time member, he has been actively taking part of the Institute’s life for decades now. 30 Jenő Egerváry (1891–1958) Member of the Academy, Kossuth Prize (1949, 1953) He was the leader of the research group at the Technical University of Budapest, the predecessor of the Institute. He has obtained outstanding results in numerical optimization. He has also worked on the three-body problem, but his most significant result is the Egerváry-Kőnig theorem about 0-1 matrices. Árpád Elbert (1939–2001) Doctor of Science (1989) His main interest was in differential equations, where he managed, among other things, to relax the conditions needed for solving semi-linear differential equations. He worked at the Institute from 1963 until his untimely death. Paul Erdős (1913–1996) Member of the Academy, member of six foreign Academies, Wolf Prize (1984), Kossuth Prize (1958), State Award (1983), Gold medal of the Academy (1991) With over 1500 papers he is, after Euler, the most prolific mathematician of all times. He worked intensively in number theory, and gave, together with Atle Selberg, the first elementary proof for the prime number theorem. In approximation theory, he proved the almost everywhere divergence of Langrange interpolation (jointly with P. Vértesi). He opened new fields in set theory, as, for example, partition theory (jointly with Richard Rado). His ideas and results also had an essential impact on discrete geometry. During the second half of his life he turned to combinatorics, where, among other things, he developed the probabilistic method. In his whole life he wandered from conference to conference and research center to research center. He was invited to lecture all over the world from Princeton to Beijing. He raised numerous famous open problems, by means of which he created entire schools in several branches of mathematics. He was officially a member of the Institute from 1972 until his death. 31 László Fejes Tóth (1915-) Member of the Academy, foreign member of four foreign Academies, Director of the Institute (1970-1982), Kossuth Prize (1957), State Award (1973), Gauss memorial medal (1974), Gold Medal of the Academy (2001). During the 1940s and 1950s, his results created a new branch of mathematics: discrete geometry. Within this field, he obtained significant results concerning extremal properties of polyhedra. He solved the 2-dimensional case of the sphere packing problem (part of Hilbert’s Problem 18). The influence of his books as well as his ability to pose interesting problems created a school around him reaching as far as the US. He was a regular organizer of Oberwolfach conferences. He worked at the Institute from 1965 until his retirement in 1983. Géza Freud (1922–1979) Doctor of Science, Kossuth Prize (1959). He was a worldwide recognized expert on orthogonal polynomials and wrote a monograph on the subject. Several of his theorems are starting points for present-day research. He developed the theory of one-sided polynomial approximation. A founder of weighted approximation, he introduced a class of weights which now bears his name. He emigrated in 1974, after 20 years spent at the Institute. Tibor Gallai (1912–1992) Corresponding member of the Academy, Kossuth Prize (1956), Academy Award (1972) He achieved his most important results in elementary combinatorial problems and graph theory. He played a key role in creating the Hungarian school in combinatorics. He worked at the Institute between 1958 and 1968. György Grätzer (1936-) External member of the Academy He is an authority in lattice theory and universal algebra. His 200 papers and books (among them Universal Algebra and General Lattice Theory) have had a great impact on the developments of these topics. He was a member of the Institute between 1958 and 1964. 32 Endre Makai (1915–1987) Doctor of Science (1955), State Award (1973), Academy Award (1970). He worked in analysis, mostly on Fourier series and differential equations. His research in applications to engineering, especially the description of the eigenoscillation of membranes, is also important. He was at the Institute between 1962 and 1980. András Prékopa (1929-) Member of the Academy, Széchenyi Award (1996) He has not only founded the Hungarian operation research school, but has also developed it to acquire international fame. The Prékopa inequality for real functions is the starting point of several profound inequalities. Though a full-time member of the Institute only in 1957/58, he conducted a group of operation research here for many years László Rédei (1900–1980) Member of the Academy, Kossuth Prize (1950, 1955) After obtaining significant results in algebraic number theory, he switched to group theory, where his research culminated in important results on factorizability of groups. He developed the theory of lacunary polynomials that later became important in combinatorics. Author of an important textbook on Algebra and several research monographs, on finite p-groups, semigroups and the foundations of geometry. Though he was very active at the Institute from the 1960’s, he was a full-time member only towards the end of his life (1971–74). Károly Sarkadi (1914–1985) Doctor of Science, State Award (1966) One of the pioneers of Hungarian statistics. He developed an exact statistical method for checking Gaussian distribution which, apart form its theoretical significance, can also be successfully applied in practice. He worked at the Institute between 1952 and 1984. 33 János Surányi (1918-) Doctor of Science (1957) His main areas of interest are logic, number theory and didactics. Together with P. Erdős, he wrote the much-cited textbook Topics in Number Theory. He is also widely known as editor of the Hungarian Problem Book, based on the problems of mathematical competitions for secondary schools. Though never a formal member, he conducted a seminar on didactics at the Institute for a long time. Árpád Szabó (1913–2002), Member of the Academy His original field of interest was ancient Greek culture. Persecuted for political reasons, he found shelter at the Institute in 1958, where he remained until his retirement in 1983. It is while working here that he became a worldwide respected authority on Greek mathematics. Author of a great number of books, many of which have been translated into various foreign languages. Károly Szilárd (1901–1980) Doctor of Science His main areas of interest were differential equations and their applications. He has obtained fundamental results about ballistics. He was awarded the Stalin Prize for work done in this area while he was a prisoner of war in the Soviet Union. Béla Szőkefalvi-Nagy (1913–1998) Member of the Academy, Kossuth Prize (1950, 1953), State Award (1978), Gold medal of the Academy (1987) As the worthy heir of Frigyes Riesz, he was the leader of the Hungarian functional analysis and operator theory school. Author of several monographs, among which the most famous one is his Leçons d’analyse fonctionnelle written jointly with his master F. Riesz, a fundamental textbook translated into six languages. Though never a full-time member of the Institute, he is the founder of the research group in analysis. 34 Lajos Takács (1924-) He initiated a new line of applying combinatorial enumeration in the theory of stochastic processes and was one of the pioneers of queuing theory. Author of several research monographs, among which the influential Combinatorial methods in the theory of stochastic processes. He entered the Institute in 1955 and worked here until his emigration in 1958. Pál Turán (1910–1976) Member of the Academy, Kossuth Prize (1949, 1952) Founder of the Hungarian analytic number theory school, he also achieved far-reaching results in approximation theory, in complex analysis and in graph theory. His famous method of power sums by which he obtained results related to the Riemann Hypothesis is exposed in his book On a new method in analysis and its applications, published in German and English. He had a number of students around the world. Though active at the Institute for decades, he became a full-time member only in 1975, a year before his untimely death. Ottó Varga (1909–1969) Member of the Academy, Kossuth Prize (1952) He obtained important results in differential geometry, especially concerning the foundations and the characterization of Finsler spaces. He spent the two last years of his life at the Institute. István Vincze (1912–1999) Doctor of Science (1972), State Award (1966), Deputy director (1950-1964) He obtained basic results in mathematical statistics and its applications and wrote a monograph on the subject. He worked at the Institute from its foundation until 1982. 35 The Rényi Prize In 1972 the Institute founded the Rényi Prize in the memory of its founder. The prize is awarded yearly (from 2001 every two years) to one or two members of the Institute having recently achieved a major result. So far the following researchers have been awarded the prize: 1972: Gábor Halász 1973: Endre Szemerédi 1974: József Szabados 1975: János Komlós 1976: Gyula Katona 1977: András Sárközy; Gábor Tusnády (refused the prize) 1984: József Beck; Péter Vértesi 1985: Zoltán Füredi; János Pintz 1986: Emil Kiss; Imre Ruzsa 1987: Hajnal Andréka; János Körner 1988: Imre Bárány; József Fritz 1989: István Berkes; Péter Major 1990: Pham Ngoc Ánh 1991: Antal Balog; Ervin Győri 1992: János Pach 1993: László Pyber; Lajos Soukup 1994: Nándor Simányi; Gábor Simonyi 1996: Endre Makai; Katalin Marton 1997: Gábor Fejes Tóth 1998: András Kroó 1999: Gábor Tardos 2000: Péter Pál Pálfy 2001: Mátyás Domokos 2003: László Márki 36 History of the Institute Hungarian mathematics acquired international fame by the end of the 19th century, as is testified by the work of such great scholars as Gyula Kőnig, József Kürschák, Lipót Fejér, Alfréd Haar or Frigyes and Marcel Riesz. At the time, research in theoretical mathematics was conducted by talented Resolution of the foundation of the Institute 37 teachers at universities, colleges, and secondary schools, as everywhere else in the world. In fact, the first independent mathematical institutes only came into being towards the middle of the 20th century, and their founding was prompted by nonscientific reasons: in the US by the flux of European immigrant scholars, and in the Soviet Union by the necessity of employing scientists whose research was valued by the regime but who could not teach for political reasons. Thus, after 1949, research institutes of the Hungarian Academy of Sciences came into being following this Soviet model, but in many fields, especially in exact sciences, the ‘condition’ for entering them was not really political (un)reliability, but rather scientific excellence. This was the case of our Institute, officially founded in 1950, but which was, however, not without a predecessor. In fact, in the second half of the 1940’s a research group in mathematics was already functioning under the auspices of the Technical University of Budapest, created following an initiative of the Ministry of Culture. Its leader was Jenő Egerváry, a significant theoretical mathematician who, having spent considerable time in Germany, was also familiar with modern applied mathematics. It is on the basis of this group that the Institute for Applied Mathematics of the Hungarian Academy of Sciences was created on August 1, 1950, following successful lobbying by György Alexits, at the time deputy secretary of state. 29-year-old young talent Alfréd Rényi was appointed as the first director, and for many years Jenő Egerváry served as President of the Scientific Board. The Institute consisted of five research divisions at first. The Division of Mechanics and Tension Analysis, under the leadership of Jenő Egerváry, was the follower of the research group at the Technical University mentioned above. The other four units were the Division of Probability and Mathematical Statistics led by Alfréd Rényi; the Division of Actuaries and Economics led by István Vincze; the Division of Numerical and Graphical Methods led by György Hajós of Eötvös University (with an exterior branch in Miskolc); and the Division of Chemical Engineering led by István Fenyő. At the beginning of the 1950’s, the main task of members of the Institute was to put their special mathematical knowledge at the disposal of industrial companies. For example, at the Division of Numerical and Graphical Methods it was possible to order calculations which could not be performed elsewhere. The statistics group, being familiar with the theory of sampling as well as with the corresponding procedures, could be helpful to quality control 38 organizations. The biometry group gave advice on performing reliable statistical analyses in theoretical medicine, or on the planning of biological and agricultural experiments. Gradually, the scope of research conducted at the institute began to widen. In the foreword of The 2nd Proceedings of the Applied Mathematical Institute, published in 1954, Rényi already mentions seven divisions: Mechanics and Tension Analysis; Probability; Mathematical Statistics; Numerical and Graphical Methods; Differential Equations; Electromechanics; and Real Analysis. As can be seen from this list, theoretical research has now gained territory besides the applied fields, prompting the necessity of restructuring and renaming the institute. This took place in 1955. As Rényi wrote in 1960, on the occasion of the 10th anniversary of the Institute’s foundation, “the manifold problems and tasks faced by the staff of the Institute... can be solved only if mathematicians’ efforts in applying results are supported by theoretical research. The Institute can now realize more efficiently the connecting of applied work to theoretical research, having been restructured under the name Mathematical Institute of the Hungarian Academy of Sciences as of August 1, 1955.” According to Rényi, “the change of name expresses that the Institute should be a home not only to applied research, but to pure mathematics as well, leading to a closer connection between theory and application. In the process of restructuring the Institute, new theoretical divisions will be established soon [...]” One of the newly established units was the Division of Complex Analysis led by Pál Turán (the predecessor of the current number theory group); another one the research group in functional analysis. Based in Szeged under the leadership of Béla Szőkefalvi-Nagy, this group is the ancestor of today’s Division of Analysis. It also furnishes a good example of a practice followed at György Grätzer, Paul Erdős, the time but abandoned later: Pál Turán and Alfréd Rényi research groups performing significant scientific work somewhere in the country became, in a way or another, attached to the institute. The 1960’s also saw the birth of a research group in abstract algebra, led by László Rédei – this was a subject already quite remote from practical applications. As Rényi writes in a spirit typical 39 for an era still suspicious about purely theoretical research: “No single division of the Institute can be considered as exclusively theoretical or exclusively application-oriented; the differences that emerge are only due to the relative importance attributed to theoretical research versus application.” Since then, the research profile of the Institute has evolved in function of scientific trends and the availability of researchers specializing in a given field. Following the influence of Pál Erdős, Pál Turán, András Hajnal, László Fejes Tóth and others, research conducted in various areas of discrete mathematics (graph theory, combinatorial set theory, discrete geometry, to name but a few) has become one of the main forces of the Institute, leading to the creation of several new divisions. In the 1990’s, young researchers having studied abroad introduced subjects that have been previously missing from the palette of the Institute, such as algebraic geometry and differential topology. The future will certainly see the emergence of new research topics; the Institute, however, does not aim at covering all fields of mathematics, only those where it can set up a strong research group. Thus it can be seen that over the years theoretical research has gradually become the dominant activity at the Institute. Applications, however, have not been forgotten. A research group directed towards economic applications started its work in 1959 under the leadership of András Prékopa. This group, later transferred to the newly founded Computer and Automation Research Institute, was the precursor of the Hungarian school in operation research that attained international fame. From the 1960’s, researchers at the institute became involved in industrial applications through individual contracts. For example, Alfréd Rényi and János Szentágothai worked together on a mathematical model of the brain. At the end of the 1970’s GANZ Equipment Works developed programs using combinatorial ideas. Differential equations describing the subterranean burning of oil fields of Zala county were also investigated. Colleagues from the Institute developed computer programs of long-range forecasting for the Hungarian Aluminum Trust, and created an algorithm for designing chips for the Company of Microelectronics. In recent years, the Institute has been successful in applying its expertise in databases and cryptography. 40 Resolution of altering the name of the Institute Thus during the past decades, the Institute underwent quite a number of transformations, but in its spirit it remains close to that of its founding director. From July 1, 1999, the Institute bears the name of Alfréd Rényi, in honour of his achievements in mathematics and scientific organization. The building of the Institute The Institute is located in a four-story historical building in the heart of downtown Budapest; see the next section for the building’s history. On the ground floor you find in particular the Director’s office, the secretaries’ room (look at the painted ceilings!) and the library of the institute. From the entrance hall you can also enter the Institute’s inner courtyard. Equipped with round tables, chairs and even a whiteboard, it is a calm and pleasant place for a mathematical discussion or just a chat when the weather is fine. It is from there that you may access the computer managers’ room. On the first floor you find mostly offices, but also the Finance Department and the main lecture room. This impressive room is suitable for seminars with up to a hundred participants. Though it still retains its original shape of a century ago (look at the cameos representing symbols of sciences and engineering!), it is also equipped with audiovisual facilities meeting the needs of the 21st century. Its excellent acoustics permit the organization of concerts (there is indeed a Christmas concert here each year); it can be also transformed into a ballroom during the Mathematicians’ Ball. The lecture room opens from a pleasant lounge suitable for discussions as well as smaller receptions. The second floor is again mostly occupied by offices, but you also find here two smaller seminar rooms called the dogs’ room and the cats’ room, respectively (ask a local colleague for the origin of these names) and another lounge. The recently created third floor is exclusively devoted to offices. 41 History of the building After its foundation, the Institute – with eleven full-time and a few part-time researchers – was housed in four offices on the second level of the main building of the Technical University. Later the Institute moved into rented rooms, among others in 31 Stalin (now Andrássy) avenue and 4 Zichy Jenő street. In 1958, it moved to its present day premises at 13–15 Reáltanoda street. Until 1887, there were two separate lots and houses on the site of the Reáltanoda building. In 1868 baron Béla Rédl bought the lot at 13 Reáltanoda street. He received permission to build a one-story palace during the same year, which is documented as an existing building by 1873. In 1886 baron Rédl bought the neighboring lot at 15 Reáltanoda street from its former owner and enlarged his palace. The present arrangement, a building enclosing a relatively large courtyard, was formed after several modifications. It was built in stages, which can be seen not only from the plans of the building but also from its facade. It is conceivable that the plans for the original palace at 13 Reáltanoda street were designed by Theofil Hansen of Vienna; those of the 1886-87 extension are by János Wagner. Baron Richard Hammerstein inherited the palace in 1907, and applied for a permission to enlarge it to a three-story building. Before the construction could have been started, he sold the building to the Hungarian Engineering and Architecture Association (HEAA) and Alajos Hauszmann, then president of HEAA, made designs for the residence. Hauszmann was one of the most sought-after Hungarian architects of his time; his most famous building is that of the Curia (Supreme Court), today Museum of Ethnography, on Kossuth square, just opposite the Parliament. His design for the Institute consisted of the addition of a third story and a representative lecture room, resulting in a beautiful and harmonious building. It served as the seat of the HEAA until 1946. Afterwards it became a ‘People’s College’ for several years, then the seat of the Confederation of Societies in Engineering and Exact Sciences. The Mathematical Institute has been the occupant of the building since 1958. The next major restructuring of the institute’s building was carried out between 2000 and 2003, approximately a century after Hauszmann’s work. Its main aim was to provide more office space for a continuously expanding institution, but also to improve general working conditions and, from the point of view of architecture, to eliminate later modifications of the building 42 and restore Hauszmann’s design as closely as is possible without confronting practical needs of the institute. The most spectacular part of this transformation was the creation of 12 new air-conditioned offices in the northern part of the institute’s attic which also gave way to the elimination of some anomalous conditions on the second floor, giving rise to the new lounge and the two small seminar rooms. On the first floor a flat from the neighbouring building was attached to the institute, thereby enlarging the office space, and the entrance hall was restored to its original shape, close to Hauszmann’s design. Finally, a fifty-year-old dream came true by the construction of an elevator in the inner courtyard. The library The library of the Institute is the most important mathematical library in Hungary, with a stock of almost 40,000 titles and over 300 periodicals arriving regularly via exchange or subscription. The basis for exchange is the Institute’s journal (see the next section). The number of library visitors is constantly increasing: while in 1977 it had 611 readers and 2044 visitors, in 1999 these figures climbed up to 1640 and 14,500, respectively. The library received computer equipment in the second half of the 1980’s; it currently uses the Corvina system for handling library procedures and for exchanging information with other libraries in Hungary. Today the catalogue of the institute’s library can also be consulted via the Internet. For local users many journals are available online and they have access to all major mathematical databases such as Mathematical Reviews and Zentralblatt MATH. The journal of the Institute The first issue of the forerunner of our current journal, the Proceedings of the Applied Mathematical Institute, was published in 1953, followed by the second and the third issues in 1954 and 1955, respectively. The next issue, published in 1956, had a modified title, corresponding to the change in the name of the Institute. These proceedings were published yearly until 1964. Our current journal, Studia Scientiarum Mathematicarum Hungarica, a scientific periodical established in 1966 and published by the Hungarian Academic Publishing House (today a branch of Kluwer Academic Publishers) is, in a certain sense, A cover of Studia 43 a continuation of these proceedings. The editor-in-chief has always been the director of the institute and the editorial board includes the heads of the research divisions. Currently, there are four issues a year, among which occasionally special issues in the honour of distinguished Hungarian mathematicians. The homepage of the Institute As any significant institution nowadays, the Institute has a homepage on the Internet, accessible at http://www.renyi.hu. Its main features include: ♦ latest news from the Institute on front page, together with a list of upcoming events; ♦ information about the Institute’s activities, open positions, training programs; ♦ a regularly updated list of mathematical seminars in Budapest and Hungary, e-mailed weekly to those who join an open subscription list; ♦ a directory of the Institute, with links to homepages of researchers and research groups; ♦ homepages of conferences organized at the Institute as well as archives for past conferences and seminars; ♦ the library’s page, with electronic access to the catalogue and (for local users) online journals and databases; ♦ practical information for visitors. Please visit this page for further information concerning the Institute. We are grateful for any comment or criticism. 44