In Memory of Per Enflo (1944–2026)
The Department of Mathematical Sciences at Kent State University mourns the passing of Professor Per H. Enflo, an extraordinary mathematician, musician, teacher, and friend. Per served our department as a University Professor for more than two decades before retiring in 2012 and remained part of our academic community as an Emeritus University Professor until his passing. He was a cherished member of our department, our university, and the wider Kent community.
Per was a mathematician of exceptional originality and independence of thought. His solutions to the approximation and basis problems, and to the invariant subspace problem for Banach spaces, transformed functional analysis. He approached problems that had resisted generations of mathematicians with imagination and perseverance, developing new methods and opening directions that others would pursue for decades. His pioneering work on the geometry of metric spaces also had a lasting influence, helping lay the foundations for connections between pure mathematics and theoretical computer science, including the design and analysis of algorithms.
Informal Analysis Seminar at Kent State University, around 1972.
Per was also a teacher and mentor to many students. Over his long career, he introduced thousands of undergraduates to mathematics and guided numerous doctoral students, both at Kent State and elsewhere. Teaching was an important part of his life. His influence continues through his former students, in their research and teaching and in the encouragement they give their own students.
Music was another essential part of Per’s life. An internationally accomplished concert pianist, he performed as a soloist and chamber musician for audiences around the world. His music meant a great deal to those of us who had the pleasure of hearing him play.
Concert at Per’s house in Kent, 2008.
To many of us, he was simply Per, a dear friend. His achievements were only one part of the person we were fortunate to know. We will remember our conversations, the ideas we exchanged, and the pleasure of his company. We will always cherish the memory of the wonderful piano concerts he gave in his own home and in the homes of his friends, including Victor Lomonosov and Richard Aron. These were special occasions that brought us together to enjoy music and one another’s company. Per helped make our department not only a great place to work, but a place where we felt at home. For us, this loss is deeply personal.
2008 Summer School on Fourier Analytic and Probabilistic Methods in Geometric Functional Analysis and Convexity, Kent State University. Everyone was getting ready for Per’s concert at his home. Notice that Per is warming his hands! Pictured, left to right: Mark Rudelson (University of Michigan), Fedor Nazarov (Kent State University), Krzysztof Oleszkiewicz (University of Warsaw), Dmitry Ryabogin (Kent State University), and Per Enflo.
We extend our heartfelt condolences to his family, friends, colleagues, and former students. We share their sorrow and will remember Per with affection, gratitude, and respect.
The world has lost an extraordinary mathematician and musician. We have lost a dear friend.
