A headshot of Dennis Sullivan. Sullivan was named the 25th laureate of the Abel Prize. PHOTO PROVIDED BY DENNIS SULLIVAN

In math professor Dennis Sullivan’s fifth-floor office, hundreds of books lie toppled against each other in Parisian bookcases.

Lush carpeting immediately separates the room from the usual whitewashed appearance of most professors’ offices and trinkets from indeterminate places adorn Sullivan’s hardwood desk. As Sullivan returns from his lunch break at 1 p.m. he scrawls out a post-it note to join the dozens of others on his front door and hands a nearby student a peanut butter cookie fresh out of the microwave.

Sullivan, 71, was recently named the 25th laureate of the Abel Prize, widely considered the mathematics equivalent of the Nobel Prize. His career has spanned six decades and 10 universities.

But Sullivan has little interest in talking about the honor, or really anything that strays too far from the subject of math. Throughout a 30-minute interview with The Statesman, Sullivan only spoke about his personal contributions to mathematics for roughly five minutes. He was perfectly content to pencil in diagrams on his plaster walls and discuss the work of Isaac Newton and the origins of calculus. 


“It’s very pleasant,” Sullivan said of the Abel Prize. “It’s like a trophy or something like that. It’s like the greatest sporting event of all time — somebody wins and somebody doesn’t win, but then a few days later, everyone’s forgotten. It’s not quite that trivial, but something like that. And it also has a nice monetary part and my graduate students will take me more seriously now.”

Sullivan’s nonchalance is unsurprising; he’s accustomed to receiving international awards by now. Still, it’s that unwavering dedication to his subject that colleagues say has enabled Sullivan’s groundbreaking discoveries and made him one of the most respected members of Stony Brook’s math department since he arrived in 1996. 

“He is really enthusiastic about math, like a kid,” Department of Mathematics Chair Alexander Kirillov said. “He’s eager to talk to new people and learn new areas of math, which is not very common for people of his age and his achievements. He asks more questions than everyone else, sometimes more than everyone else combined.”

Sullivan’s work focuses on algebraic topology, a modern version of geometry concerning the deformation of shapes. It was also the subject of Sullivan’s doctorate thesis at Princeton University in 1966. In topology, two shapes are considered congruent, or identical in form, if they can be reshaped to look the same without destroying them. Because a triangle can be compressed into a circle, they are topologically equivalent. 


“Dennis P. Sullivan has repeatedly changed the landscape of topology by introducing new concepts, proving landmark theorems, answering old conjectures and formulating new problems that have driven the field forwards,” Hans Munthe-Kaas, chair of the Abel committee, said in a press release. “Sullivan has moved from area to area, seemingly effortlessly, using algebraic, analytic and geometric ideas like a true virtuoso.”

Sullivan, though, says his work is based on very simple ideas. As evidence, he cites the composition of a brick wall. Laying the bricks so that they interlock produces a stronger wall than piling the bricks directly on top of each other — a concept of space relevant to algebraic topology, but also just plain common sense. 

“It’s a very basic idea,” Sullivan said. “Something like this, I can explain to a three-year-old. After a little experience, you change it and start alternating.”

As part of the Abel Prize, Sullivan will be awarded 7.5 million Norwegian kroner — nearly $1 million — and meet with King Harald V in Oslo, Norway on May 24.

“When you get that much money, it’s a responsibility,” Sullivan said. “You have to do something. If it were like $10,000, you could just go to Hawaii. I don’t want to say it’s better, but there’s a difference.”


Sullivan has been the thesis advisor for 39 graduate students, including 14 at Stony Brook. His teaching has been directly or indirectly responsible for 146 dissertations, according to the Mathematics Genealogy Project.

“He’s very popular with [graduate students] in the department,” Kirillov said. “It’s very common for Dennis to start talking about something tangential to the declared syllabus and then go on a long and winding road. You see how his thinking works? He is arriving at new ideas rather than just presenting established material.”

Sullivan’s love of teaching is reflected in his philosophy about his field. He says math is something “very natural” that has become too far removed from the questions children instinctually ask: How big is the universe? How far do numbers go?

“It’s sort of sad that math, because it’s useful, it has to be taught to a lot of different people in a quick way,” Sullivan said. “It’s actually very simple — can be understood by children. It’s only the older ones that have problems. There’s something a little wrong here.”


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