From Sandwich Maker to Mathematician

The person behind the glass at your local sandwich shop, smothering your BLT with extra mayonnaise, could be a genius mathematician. Not only that, they could go on to solve one of the world’s most challenging math problems — the twin primes conjecture. 

I struggled in my high school math classes — big time. I’d bounce from one friend’s house to the next to get help with homework. They’d sympathetically explain the concepts repeatedly, amazed at my inability to grasp basic ideas. One time in Geometry, I spent an entire week studying, determined to ace the next test. During the examination hour, I felt prepared and cautiously worked my way through the problems. 

Several days later, the teacher, Ms. Grubbs, returned our marked-up exams. I watched as one-by-one my friends received theirs. Their delight was unmistakable, a look that could only mean one thing — they had aced it. My confidence rose as Mr. Grubbs bounced around the room before finally stopping at my desk. I could feel my blood pressure rise, and when she placed the paper on my desk, I could hardly look. But I did—a 39…out of 100.

That test still scars me, but my struggles in math have led me to admire people who have the intelligence and determination to solve complex problems. 

When we meet someone, we tend to write their stories on the fly. A brilliant mathematician doesn’t fit the narrative of a fast-food worker, so we don’t consider it. Unfortunately, we write off a lot of people based on where they work, how they dress, or their mannerisms. 

Less than two miles from where I sit writing this is the downtown Lexington Subway restaurant. I recognized Main Street and several buildings in the background of a photo I recently stumbled upon, but I didn’t recognize the photo’s subject, which I learned was Yitang Zhang. He’s standing in front of the Subway, some bright yellow flowers beside him, not quite frowning, but not smiling. 

I don’t know who to attribute this photo too. If you know, please reach out to me.

As it turns out, Zhang ended up in Central Kentucky after earning a doctorate from Purdue University in 1991. Despite his advanced education, he had difficulty finding work in academia, even resorting to living out of his car for several periods. He caught a break when a friend opened a Subway in Lexington and offered him a job — mostly keeping the books but assembling a sammy now and again as needed.

Zhang is originally from Shanghai, China. When I was nine years old, I dreamed about being a professional athlete, but Zhang dreamed about solving great math problems. A Business Insider profile described his precociousness: 

“He was ten when he first learned about two famous number theory problems, Fermat’s last theorem, and the Goldbach conjecture. While he was not yet aware of the centuries-old twin primes conjecture, he was already taken with prime numbers, often described as indivisible “atoms” that make up all other natural numbers.”

Zhang’s first significant setback happened when his education was cut short. The Cultural Revolution (1966–1976) was a violent decade in China that resulted in attacks on teachers and professors, causing many schools to close. Zhang’s father was not on good terms with the Communist Party, so Zhang couldn’t attend high school, spending ten years as a laborer instead. He spent his free time reading books to continue his studies. 

After the revolution, Zhang continued his studies at Peking University, becoming a top math student. His prowess led to his recruitment to Purdue University to pursue a Doctoral degree under the tutelage of T.T. Moh. 

Zhang experienced another major setback after graduating from Purdue. According to The New Yorker:

“Zhang had received a Ph.D. in algebraic geometry from Purdue in 1991. His adviser, T. T. Moh, with whom he parted unhappily, recently wrote a description on his website of Zhang as a graduate student: “When I looked into his eyes, I found a disturbing soul, a burning bush, an explorer who wanted to reach the North Pole.” Zhang left Purdue without Moh’s support, and, having published no papers, was unable to find an academic job.”

During the next seven years, Zhang bounced around, working odd jobs, including his stint at Subway. Finally, in 1999, Zhang made it to academia, becoming a lecturer at the University of New Hampshire. He turned his focus to the twin prime conjecture, which Quanta Magazine says “concerns pairs of prime numbers with a difference of 2. The numbers 5 and 7 are twin primes. So are 17 and 19. The conjecture predicts that there are infinitely many such pairs among the counting numbers or integers.”

Erica Klarreich explained the origin of his work, saying, “The seeds of Zhang’s result lie in a paper from eight years ago that number theorists refer to as GPY, after its three authors — Goldston, János Pintz of the Alfréd Rényi Institute of Mathematics in Budapest, and Cem Yıldırım of Boğaziçi University in Istanbul. That paper came tantalizingly close but was ultimately unable to prove that there are infinitely many pairs of primes with some finite gap.”

In 2010 Zhang went from unknown and unheralded to in high demand. He submitted his proof of a bounded prime gap lower than 70 million to the Annals of Mathematics, a prestigious journal. The math community was in awe. One of the journal’s referees said, “The main results are of the first rank,” and declared Zhang had proved “a landmark theorem in the distribution of prime numbers.”

Zhang’s work led to numerous awards, including the prestigious MacArthur Award in 2014. His rise is a testament to his perseverance. In addition to anti-intellectualism interrupting his education and a lack of mentorship while studying in the United States, Zhang also had to contend with a shy and quiet personality. His genius was not immediately evident, on which Zhang said, “My personality didn’t allow me to be very public, to be known by everyone, because maybe I’m too quiet.”

The obstacles he faced were also kept quiet. He didn’t demand help or seek attention. He kept going. As I go about my life, I’ll try to remember there are many Zhangs out there. They might not work glamorous jobs, earn a lot of money, or get the attention of their peers — but if they keep going, they will contribute something meaningful (even if it’s not the solution to a mathematical quandary.)

Through this lens, we can see the humanity in everyone, despite our struggles. Or, as Hierocles put it:

“Act by everyone, in the same manner as if you supposed yourself to be him, and him to be you.”