22/11/2019

With over 5,000 goals, Gugu is a star on the field and in the Brazilian Mathematical Olympiad (OBM).

Luiza Barata

It's not listed on the Lattes Platform, but Carlos Gustavo Tamm de Araújo Moreira is a father, a Flamengo fan, a fan of the Brazilian Mathematical Olympiad (OBM), and a prolific goalscorer. An idol among Olympians, as participants in academic competitions are called, he is known worldwide as Gugu. His love for numbers is evident in almost everything, even when playing soccer: he insists on officially recording the goals of matches with IMPA students at the Clube dos Macacos in Horto. “When I was close to scoring five thousand goals, I left the game. I saved them for the next match, to organize a celebration. When I reach a thousand goals, I'll have a barbecue. Today, it's already 5,532,” says the mathematician, without modesty, who has scored far more goals than Pelé (“only” 1,282).

Even at the 2018 ICM (International Congress of Mathematicians), where he gave a plenary lecture, everyone called him Gugu. "My family still calls me Carlinhos, but only my wife calls me Carlos Gustavo."

Gugu's friendly spirit and good humor are trademarks that he makes a point of displaying, along with the Flamengo crest and the political pins that are almost always on his shirt. The researcher has been at IMPA since 1997 and, for the past seven years, has been responsible for the OBM (Brazilian Mathematical Olympiad). When he's not dealing with numbers, Gustavo enjoys attending samba gatherings and debating politics.

His relationship with mathematics began early. “Between the ages of 11 and 12, when I went to visit my family in Belo Horizonte (MG), I saw a cousin who was already starting to study computer science. He had a very large calculus book. I convinced my father to buy one for me at the Book Fair.” Soon after, he got to know IMPA and took a scientific initiation course. Gugu obtained good grades, was introduced to the vice-director at the time, Elon Lages Lima, and began participating in olympiads.

Gugu é coordenador-geral da OBM

This shift gave him a very different adolescence from his peers and an academic background that deviated from the usual chronological order. “I went to school in the morning, came to IMPA in the afternoon. I ended up doing, more or less, the master's program alongside school. I was the youngest in the class. A small group of nerds from Colégio Santo Inácio thought that was the coolest thing ever. I even brought some of them to study with me.” Curiously, he believes it was easier to be at IMPA than at school. “There (at school) there were eight or nine subjects to keep up with… Here (at IMPA), there were only two!”

But the routine was a source of concern for his parents. The mathematician, son of anthropologist Carlos de Araújo Moreira and English teacher Anna Lucia Tamm, laughs when he recalls that the two anxiously awaited their son's return home to Copacabana every day. "I divided my time between school, IMPA, and politics. I would leave in the morning and sometimes only return very late."

At 17, Gugu faced the challenge of defending his master's thesis, "Centralizers of Circle Diffeomorphisms," under the guidance of Jacob Palis. Between his master's and undergraduate studies, he accumulated other important titles. He won his first gold medal at the Wednesdays Ibero-American Mathematical Olympiad, bronze at the 30th International Mathematical Olympiad (IMO), and gold at the following edition. While participating in competitions, he visited countries such as Cuba, China, Germany, and Spain.

Only then did he complete his undergraduate degree. He studied mathematics at UFRJ and, within a year, already had his diploma in hand. "Since the master's degree came first, I was exempted from many subjects." The partnership with Jacob Palis continued to bear fruit: back at IMPA, he continued with his advisor during his doctorate, completed in 1993, at the age of 20.

He then went to France, where he lived for two years. It was there that he met Fields Medalist Jean-Christophe Yoccoz, whom he remembers fondly. “He was my postdoctoral advisor at the University of Paris-Sud and a mathematician who was a great friend of Brazil. He died young, at 59, and had a very close relationship with us. We worked in Portuguese. He was a very important person for the beginning of my career.”

Gugu ao lado de Jacob Palis, Welington de Melo e Marcelo Viana

Life abroad wasn't all joy. Perhaps it was the period where the age difference between him and the other students weighed most heavily. "I was very young at the time, and it wasn't very easy living outside of Brazil. Post-doctoral work is a somewhat solitary career, so I didn't really have my group of friends there."

As soon as he returned to Brazil, Gustavo secured a research fellowship from CNPq, which he held from 1995 onwards. The following year, he ran for city council in Rio de Janeiro. “There’s a legend that my speech on television went something like this: ‘Comrades, I’m Gugu, candidate for city council for the Communist Party, number 21,603. You know my work; I proved that the intersection of stable sets of irregular corners is dense in the region where the sum of the dimensions is greater than one. Vultures vote for Gugu.’ Some people say they saw it on television, but that’s a lie…my candidacy was accidental,” he says, laughing. The desire to become a politician is now in the past.

The researcher considers his field of work to be "somewhat dispersed." His main area of expertise is dynamical systems and fractal geometry. However, he occasionally pursues studies related to number theory and combinatorics. Currently, he divides his research time between ten months at IMPA and another two in China, where he teaches at Nankai University.

One specific topic he has been tackling in recent years is the Lagrange Spectrum, which, in short, seeks to approximate real numbers to irrational numbers. "These are beautiful things in mathematics that connect areas that, seemingly, have nothing to do with each other, but end up having profound relationships."

This relationship seems to extend to his personal life as well. "Especially in high school, what motivated me a lot was that mathematics doesn't depend on authority figures; it's something you can figure out for yourself. You can verify, by yourself, whether what the teacher says is right or wrong. It's not like history, where you can't personally verify it at that moment."

Sistemas Dinâmicos: Enrique Pujals, Gugu, Artur Avila, Jacob Palis, Welington de Melo e Jean-Christophe Yoccoz

The researcher had a son, Carlos (10 years old), with the mathematician Raquel Scarpelli, to whom he was married. Today, Gugu lives with his son, his current wife, Maria do Carmo de Brito Tamm de Araujo Moreira, and his stepdaughter Gabriela. At age 8, Carlos even participated in an article with his father published in the “Revista do Professor de Matemática” (Mathematics Teacher's Magazine). The habit, of course, comes from home. The passwords for the family's video games are formed by sequences of digits of the number Pi: therefore, Carlos needs to know them by heart. From hearing so much about number categories, Carlos created his own: what he called assemblage numbers, the subject of the article with his father. These are numbers formed by digits that appear within Pi, without repeated digits. For example, 14, 1592, and 35897.

In Gustavo's office at IMPA, the Erdös Prize, awarded in 2018 for his contribution to Olympic mathematics, occupies a prominent place. The researcher says that the Olympiad committee does a little bit of everything to manage the competition aimed at elementary, middle, and university students from public and private institutions. "We train the teams that will compete, create the problems for the exams, conduct training sessions throughout the country, and organize the annual awards ceremony."

For him, the most important role of the Olympiad is to show the general public that research in mathematics is something current and a promising career. "Most people believe it's something invented centuries ago. But it's a living science; there's much more to discover." According to him, the tests go beyond the Olympic universe and stimulate participants and the teaching of the subject in general – since teachers exchange experiences, tips, and develop more creative problems.

A fan of football and math competitions, Gugu doesn't consider himself a "very competitive" person. "But some people say I am," he laughs. One of the highlights of Olympic Week, when the OBM awards ceremony is held annually, for him, is the "Olympic revenge" moment, when it's the students' turn to create challenging questions for teachers to solve. "Sometimes I lose… but it's one of the coolest moments of the event."