To them he is just “Laci” – top mathematicians honour László Lovász in Budapest

For the second time after a ten-year-long interval, Budapest hosted a conference for the international community of mathematicians for five days. The scientists listenedGallery of the event to lectures, held debates and discussed questions all related to the oeuvre of the current president of the Hungarian Academy of Sciences. The “Building Bridges II” conference was opened on Monday in ELTE Gólyavár. “It is the second one, as the first one was organised ten years ago, and it is about bridges, because Laci’s results have built a number of bridges between mathematics and the different branches of computer science,” said Péter Pál Pálfy, Head of the MTA’s Alfréd Rényi Institute of Mathematics, in his opening speech. He also added that the Institute auditorium, which accommodates 100 people, proved to be too small for the conference.

It is no surprise that so many people were interested in the conference, as several renowned lecturers were participating, whose names strike a chord even for those who are not experts in their subfields. Let us just mention Endre Szemerédi, Abel Prize winner, or Terence Tao, who is considered to be a child prodigy for his achievements. László Lovász was also considered a child prodigy by many, winning all of his youth mathematics contests – though he never behaved as a stereotypical scientist. Péter Pál Rényi caused great amusement when he recalled that Lovász earned his PhD degree at the age of 22 – before graduating from university and obtaining an MSc, causing some administrative problems for legislators.

credit: mta.hu/Tamás Szigeti

Lovász’s career started in a class specialised in mathematics at the Fazekas Secondary Grammar School, in Budapest, 1962. His teacher and mentor was Imre Rábai. It was in his first year at this school that he met Miklós Simonovits, with whom he has worked together on several problems.

“László Lovász is a true polymath, which is really rare in the field of mathematics, which now has so many different branches. I can only think of two examples like him among my professors, Pál Erdős and Pál Turán,” Simonovits said. “Most mathematicians dedicate themselves to algebra, geometry or analysis. Lovász’s first outstanding results came from the field of algebra when he was still a student. He started to work in the geometry department, and his latest book contains various ideas from the realm of analysis.”

However, if we examine the background of all these subject areas, we find combinatorics (how things can be counted), graph theory (what rules are valid for a network) and the theory of algorithms (how to write a step-by-step solution to a problem – that is, basically everything a computer does). All of these were mentioned when he won his two most outstanding awards, the Wolf Prize in 1999 and the Kyoto Prize in 2010.

It is not only Lovász’s oeuvre that is versatile, but also his way of thinking. As Miklós Simonovits said, “Some mathematicians think in pictures, while others think in formulas – Lovász applies both methods. Some scientists are good at setting up theories, while others excel at problem solving – Lovász starts to solve a problem interesting to him with a rich inventory of strategies, and when he has arrived at the solution, he goes on and very often lays the foundation for new theories.” The best example for this is his latest book on extremely large networks, which is already regarded as a basic foundation for a new theory. “He always exerts considerable influence on his environment with his results. Here I am not only thinking about his subject matter areas, but the fact that people can gain new points of view when talking to him,” added Simonovits.

A full house reception credit: mta.hu/Tamás Szigeti

Two mathematical physicists also delivered lectures during the conference, both of whom played a decisive role in Lovász’s eight-year-long research in the United States. Jennifer Chayes and Christian Borgs were the leaders of the research group in which Lovász worked at Microsoft, where they synthesised the needs of basic research and applications. He also became a mentor to Balázs Szegedy there, who had this to say of those times: “László Lovász belongs to a legendary generation of Hungarian mathematicians, which I can only compare to the Golden Team of Hungarian footballers. Around 2004, I was lucky enough to start work with him when he began to lay the foundations for a new subject area. A new mathematical theory began to form, in which huge graphs could be examined with the help of limit value calculations used in mathematical analysis. Lovász was a leader in this new field of research, and he invited me to join in. I could see him working, which determined my working style from then on. I could see how the vision of Mr Lovász (who goes by the nickname “Laci” to his mathematician friends) came to fruition, and I was able to help elaborate the details. We have published a number of articles together, and we were jointly awarded the Fulkerson Prize in 2012.” It goes without saying that Balázs Szegedy was among the speakers at this conference.

Several young scientists are sitting in the rows of the lecture hall in Gólyavár, which is probably due to the fact that one of Lovász’s important missions is to educate new generations. As Balázs Szegedy put it: “He summarises his scientific findings in well-written, easily comprehensible books and textbooks, and he offers inspirational university courses. He treats young mathematicians with endless modesty and openness. Although he is an exceptionally renowned scientist, anyone who has an interesting problem or solution in mathematics can speak to him.”