It’s 9 a.m. on a Friday in November and yet a steady stream of students is already making its way into Professor of Mathematics Leslie Cheng’s office in Park. The reasons for each visit vary slightly—help with a difficult equation, advice about a course selection, a recommendation for an internship.
“Leslie cares deeply about each of her students and goes to great efforts to support them,” says fellow Professor of Mathematics Lisa Traynor. “In all my years of having her as a colleague, I have never heard her express any frustration at any student. Her patience and belief in the potential of all students is admirable.”
In recognition of her commitment to her students, teaching excellence, and scholarship, Cheng was awarded the Rachel C. Hale Chair at the 2018 Commencement ceremony. To mark this honor, she will be giving a lecture on “My Journey Through Harmonic Analysis” on Thursday, Nov. 29, from 4:30-5:30 p.m. in Room B21 of Carpenter Library. A reception in the London Room will follow the event.
Harmonic analysis is the branch of mathematics that studies the representation of signals or functions as the superposition of basic waves. The basic waves are called “harmonics," hence the name “harmonic analysis." In the past two centuries, it has become a vast subject with applications in areas as diverse as signal processing, quantum mechanics, and neuroscience.
Cheng’s research addresses some of the theoretical aspects of the field. Her results, some jointly with other collaborators, have appeared in various mathematical journals such as Proceedings of the American Mathematical Society, Michigan Mathematical Journal, Studia Mathematica, a Polish mathematics journal founded in 1929 that publishes original papers in English, French, German, or Russian, mainly in functional analysis, abstract methods of mathematical analysis, and probability theory, and Collectanea Mathematica, an international journal of the University of Barcelona and the oldest mathematical journal in Spain.
Cheng’s time at Bryn Mawr didn’t begin at the front of the classroom. In 1988 she came to Bryn Mawr as an undergraduate expecting to major in French or English, but, like so many others, an encounter with now Professor Emeritus of Mathematics Rhonda Hughes changed her academic path.
After an unsuccessful attempt at calculus in high school, Cheng’s guidance counselor told her parents, “that I’d be successful in life as long as I stayed away from math.”
Heeding the counselor’s advice, Cheng met with Hughes to find out what the least challenging courses were that she could take to fulfill the College’s quantitative requirement.
“Meeting Rhonda was a defining moment in my life. She said, ‘I think you should take calculus, you might get it better here than you did in high school,’” recalls Cheng. “I went to her calculus class and it was too good to be true. I actually understood what was going on. Rhonda is such an amazing professor that I started to like math.”
Calculus II followed and before she knew it, Cheng was majoring in math and earned her undergraduate degree as a member of the class of 1992.
After earning her Ph.D. at the University of Pittsburgh, Cheng applied to upward of 40 positions and had several offers, but her heart remained at Bryn Mawr, where an interim position became available.
“My Ph.D. adviser said, ‘You have tenure track job offers,’ but I was young and I wanted to come back to Bryn Mawr.”
Cheng was able to continue to work in adjunct and interim positions until a tenure track position became available in 2002 and has remained at Bryn Mawr since.
“The time has gone by so fast; it seems like yesterday when I started working here.”
In addition to advising math students, Cheng has served as a mentor for the Class of 2019 Boston S.T.E.M. Posse since June 2015.
While this Posse does have several math majors, Cheng says her goal has been to support the students no matter what their major and to try not to steer them toward any particular field.
“I truly believe that our students can accomplish whatever they want in life and the best thing I can do is to provide encouragement and support.”