Marcel Dall’Agnol joins the department as teaching faculty, bringing expertise in theoretical computer science

Marcel Dall'Agnol. Photo by David Kelly Crow

After graduating with a bachelor’s degree in engineering from the University of São Paulo in Brazil, Marcel Dall’Agnol started an unlikely first job: teacher at an elementary school for disadvantaged students.  

For Dall’Agnol, who is now a teaching faculty member in the department of computer science at Princeton, the experience was life changing. “I love teaching,” he said. “I love seeing when something clicks for students. It’s just so rewarding.”

In addition to teaching, Dall’Agnol also loves math. His interest in math eventually prompted him to leave his teaching job to pursue a master’s degree at the National Institute for Pure and Applied Mathematics in Brazil, and later a doctoral degree in computer science at the University of Warwick in the United Kingdom.

His research focus is theoretical computer science, particularly sublinear algorithms, interactive proofs and quantum computation. “Theoretical computer science is essentially math,” Dall’Agnol said. “But the questions we ask are inspired by computer science.”

One central line of questioning in his research stems from an unsolved computer science mystery: the P vs. NP problem. This is one of six unsolved Millenium Prize Problems — the most important unanswered questions in mathematics. Essentially, the P vs. NP problem asks whether it’s quicker to solve a problem or verify that an answer to a problem is correct, said Dall’Agnol. “It seems intuitive that it’s easier to verify,” he said, “but no one has been able to prove it.”  His dissertation research looked at a related question about whether certain problems can be solved more efficiently using quantum or classical computation.  

His more recent work is concerned with how quantum computing will impact cryptography. “People say that quantum computers will break all cryptography. That’s not quite right,” Dall’Agnol said. But is it harder to prove that cryptography will remain secure against the power of quantum computing. Dall’Agnol is working on research to prove that certain kinds of existing cryptography can work against a quantum adversary.

After completing his Ph.D., Dall’Agnol arrived at Princeton in September 2023. He is currently one of 13 teaching faculty members in the department. He’s enjoying the role, he said, because while he gets plenty of opportunities to teach, he still has time to pursue other interests. “I have time to do research,” said Dall’Agnol. “I can create an outreach program. I can spend an entire week working on a lecture. It’s incredible.”

This semester he’s co-teaching COS 445: Economics and Computation, alongside Matt Weinberg, associate professor of computer science. The course covers an array of topics related to theoretical computer science, including algorithmic thinking and game theory. Next semester, he will be an instructor in COS 226: Algorithms and Data Structures. And in the future he hopes to advise independent work that focuses, he said, “on really cool math.”