Jacobus Fellows: Cibinel, Hagos, Ren and Nguyen win Princeton’s top graduate student honor

Princeton University: Pietro Cibinel, Rama Hagos, Tung Nguyen, and Zhiyi “Allen” Ren have been named winners of the Porter Ogden Jacobus Fellowship, Princeton University’s top honor for graduate students.

The Jacobus Fellows will be honored at Alumni Day(Link is external) ceremonies on Saturday, Feb. 22.

Established in 1905, the fellowships support each winner’s final year of study at Princeton. They are awarded to one Ph.D. student in each of the four divisions — humanities, social sciences, natural sciences, and engineering — whose work demonstrates the highest scholarly excellence.

Tùng Nguyễn

Nguyen, a fifth-year doctoral student in applied and computational mathematics who came to Princeton in 2020, earned a bachelor’s degree in mathematical sciences from the Korea Advanced Institute of Science & Technology, Daejeon.

When Nguyen arrived at Princeton, he developed a simple research process: Fill a whiteboard with ideas, then think about the problems. His novel thoughts have led to significant breakthroughs that had long eluded scholars working on a central open problem in graph theory since the 1970s. His dissertation, “Induced Subgraph Density,” focuses on the local-global property in mathematics, specifically this phenomenon in graph theory. His research centers on the idea that complete disorder is impossible in any large system. He seeks to identify a coherent and ordered structure within a large system.

“One of the central open problems in my area is the Erdős–Hajnal conjecture from 1977,” Nguyen said. “It is a wonderful example of the local-global phenomenon in graph theory. It says that even as long as you impose just a tiny bit of local structure in your system, something global is going to happen.”

Nguyen’s research centers on “enormous graphs,” which he examines to see if they might contain a little graph. If identified, he examines whether the little graph might have specific patterns. He hopes this research can improve the efficiency of real-world algorithms that transmit information between two computers in a large system, overcoming obstacles by identifying them and understanding the system’s structure.

“The main reason that we want to improve the function is because we want to find new methods of controlling very large systems,” Nguyen said. “We want to understand more about the structure of the large system. If you can understand how this large system behaves, there will be a chance that you can design a very efficient way to connect two arbitrary points in the system.”

His adviser, Paul Seymour, the Albert Baldwin Dod Professor of Mathematics, credits Nguyen with significant breakthroughs in their research of local-global graph theory.

“Tung worked by himself and would come back a couple of days later saying, ‘I think I can do this,’ which he obviously couldn’t do because it would be way too great a thing if he could do that,” Seymour said. “So, we’d check it, and five or six times, he was right. He could do this thing that was way beyond what we hoped.”

In addition to his research, Nguyen has assisted in teaching six courses during his time at Princeton. Over the past five years, he has given 20 invited talks and a five-lecture minicourse around the world to present his research.

Nguyen hopes to stay in academia for the rest of his career, continuing as a postdoc before pursuing a position as a tenured professor in a university mathematics department.