How Chinese mathematician Yu Deng went from aspiring professional Go player to Fields Medal winner

Deng, 37, a mathematics professor at the University of Chicago, and fellow mathematician Hong Wang made history by becoming the first Chinese citizens to win the Fields Medal at the International Congress of Mathematicians in Philadelphia, U.S. on July 23. The prize is widely regarded as the "Nobel Prize of mathematics."

Chinese-born mathematicians Shing-Tung Yau and Terence Tao also won the Fields Medal, in 1982 and 2006, but neither held Chinese citizenship at the time, according to CNN.

Over the past two years, Deng and his collaborators have attracted international attention for a series of papers resolving key aspects of Hilbert's Sixth Problem, one of the 23 landmark mathematical problems proposed by German mathematician David Hilbert at the ICM in 1900.

The problem seeks to explain how the chaotic motion of countless microscopic particles gives rise to the large-scale behavior of gases, fluids and waves. Deng's work provided rigorous mathematical proof for key parts of that connection, overcoming a challenge that had frustrated mathematicians for decades.

The breakthrough is widely regarded as overcoming a barrier that had stood for more than 50 years while introducing a new mathematical framework known as molecular decomposition.

Chinese mathematician Yu Deng. Photo courtesy of IMU

Born in 1989 in Shenzhen, southern China, Deng was a quiet child who preferred reading at home. His father, a computer programmer, often took him hiking and challenged him with combinatorics problems, the branch of mathematics concerned with counting and patterns.

Deng also excelled at Go, the ancient Chinese strategy board game, and once dreamed of becoming a professional player.

"Playing Go was something that allows you to focus on a single thing for some time, usually two or three hours," he told Quanta Magazine in a July interview. "I enjoyed that."

His ambitions changed after he twice failed to qualify for China's national professional Go tournament.

"There was a choice," he said. "Either Go or math. Since I lost, I decided to move my focus to math."

He then turned his attention to the International Mathematical Olympiad (IMO), the world's most prestigious mathematics competition for high school students. Although he had already completed the entire high school mathematics curriculum by ninth grade, he twice failed to make China's national IMO team.

Rather than giving up, Deng intensified his preparation. In 2006, he won the Chinese Mathematical Olympiad with a perfect score before capturing a gold medal at the IMO.

"At that time, I realized, okay, so maybe I do have some talent in math," Deng said in an interview with the University of Chicago.

The achievement earned him admission to Peking University's School of Mathematical Sciences in 2007. He transferred to the Massachusetts Institute of Technology in 2009 and graduated with a bachelor's degree in mathematics in 2011 before earning a doctorate at Princeton University and completing postdoctoral research at New York University.

Early in his career, Deng focused on partial differential equations, mathematical tools used to describe complex wave systems, from ocean waves to light traveling through fiber-optic cables. But progress proved elusive, and he temporarily shifted to other areas because he believed the field lacked the mathematical tools needed to solve its hardest problems, according to The New York Times.

In 2018, Deng joined the University of Southern California as a tenured professor. Around that time, a conversation with a colleague inspired him to revisit his earlier research, eventually leading him to Hilbert's Sixth Problem.

The hardest stage came between 2019 and 2020, when Deng and his collaborators had to develop entirely new mathematical tools with little previous work to build upon. They worked day and night, often to the point of exhaustion.

Deng recalled relying on energy drinks and rarely leaving the house while finishing the research. During a visit to his parents in China, his mother noticed how completely mathematics consumed his attention. They would be eating or talking, she recalled, "when suddenly a math problem would flash into his mind. We'd know at that moment we should stop talking, as he had already entered his own mathematical world."

In August 2024, the three mathematicians completed a 200-page paper solving the more than 120-year-old Hilbert problem for long time scales. That paper, followed by another published a year later, was widely hailed as a landmark achievement. Alexandru Ionescu, Deng's doctoral adviser at Princeton, said the work would "almost certainly win a Fields Medal".

During a news conference after the ICM, Deng called the award "a really great honor," according to the South China Morning Post. He recalled receiving an email in January from the president of the International Mathematical Union requesting a Zoom meeting. Knowing Fields Medal winners are typically informed around that time, he immediately understood what it likely meant.

"I thought that was it," he said. "So then I just kept reading the novel."

Deng has also received the Clay Research Award, the Oberwolfach Prize, the MCA Prize from the Mathematical Council of the Americas, and the Gold Medal of the International Consortium of Chinese Mathematicians.

Although the Fields Medal transformed his career, Deng said it also eased the pressure he had long placed on himself.

"I have less pressure," he said. Which means that "you can just think about math, as you want."

"We'll see how much I can get to."