Jacob “Jaap” Korevaar (25 January 1923 – 18 March 2025) was a distinguished Dutch mathematician whose career spanned several continents and decades. He held faculty positions at some of the world’s most respected universities, was elected to the Royal Netherlands Academy of Arts and Sciences, and received two of the most prestigious prizes in the United States for mathematical exposition. Korevaar’s work is remembered for its clarity, particularly his celebrated essay on Louis de Branges’ proof of the Bieberbach conjecture, which earned him the 1987 Lester R. Ford Award and the 1989 Chauvenet Prize. In 2012 he was named a fellow of the American Mathematical Society, a recognition that underscored his lifelong commitment to advancing mathematics and educating future generations. He lived to the remarkable age of 102, passing away in Bussum on 18 March 2025.
Early Life and Education
Born on 25 January 1923, Jacob Korevaar grew up in the Netherlands during a period of rapid social and scientific change. While the precise details of his childhood schooling are not recorded in the source text, it is clear that his formative years coincided with the interwar period, a time when Dutch mathematics was gaining international recognition through figures such as G. H. Hardy and W. S. Cauchy. Korevaar would later become part of this tradition, contributing to the global mathematical dialogue through his teaching and writing.
His early academic formation would have involved rigorous study in the mathematical sciences, a path typical for Dutch scholars of his era. The Netherlands has long been known for its strong university system, especially in mathematics, and it is likely that Korevaar’s undergraduate and graduate work were conducted within this environment before he began his international career.
Academic Career
University of Amsterdam – Korteweg–de Vries Institute
Before moving abroad, Korevaar served on the faculty of the University of Amsterdam, specifically at the Korteweg–de Vries Institute for Mathematics. This institute, named after the Dutch mathematicians Diederik Korteweg and Gustav de Vries, is renowned for its research in partial differential equations and mathematical physics. The institute has produced many influential mathematicians, and Korevaar’s presence there positioned him within a vibrant community of scholars working on advanced topics in analysis and applied mathematics.
University of California, San Diego
Korevaar later joined the faculty of the University of California, San Diego (UC SD). UC SD’s Department of Mathematics, established in the early 1960s, quickly became known for its research in functional analysis, partial differential equations, and dynamical systems. As a faculty member, Korevaar would have taught courses, supervised graduate students, and contributed to the department’s growing reputation as a center for mathematical excellence.
University of Wisconsin–Madison
In addition to his tenure in the United States, Korevaar also held a faculty position at the University of Wisconsin–Madison. The University of Wisconsin–Madison’s Mathematics Department has a long history of excellence, dating back to the 19th century. Its faculty members have made significant contributions to a wide range of fields, including number theory, topology, and mathematical logic. Korevaar’s association with this institution further underscores the breadth of his academic influence.
Honors and Recognition
Royal Netherlands Academy of Arts and Sciences
In 1975, Korevaar was elected a member of the Royal Netherlands Academy of Arts and Sciences (KNAW). The KNAW, founded in 1808, is the premier Dutch society for the promotion of science and scholarship. Membership is considered one of the highest honors a Dutch scientist can receive, reflecting both national recognition and international esteem. Korevaar’s election to the academy highlights his standing within the Dutch scientific community and his contributions to the advancement of mathematics in the Netherlands.
Lester R. Ford Award (1987)
Korevaar received the 1987 Lester R. Ford Award for his essay on Louis de Branges’ proof of the Bieberbach conjecture. The Lester R. Ford Award, presented by the Mathematical Association of America (MAA), recognizes outstanding expository writing in mathematics. The award emphasizes clarity, accessibility, and the ability to communicate complex ideas to a broad audience. Korevaar’s essay exemplified these qualities, making a landmark proof understandable to students and scholars alike.
Chauvenet Prize (1989)
Two years later, in 1989, Korevaar was honored with the Chauvenet Prize, also awarded by the MAA. The Chauvenet Prize is one of the most prestigious awards for mathematical exposition, given annually to an essay that is both technically accurate and exceptionally clear. Korevaar’s award-winning essay on the Bieberbach conjecture demonstrated his mastery of complex analysis and his skill in translating sophisticated proofs into engaging narrative.
Fellow of the American Mathematical Society (2012)
In 2012, Korevaar was named a fellow of the American Mathematical Society (AMS). The AMS fellowship program, established in 2012, recognizes members who have made outstanding contributions to the creation, exposition, advancement, communication, and utilization of mathematics. Korevaar’s election as a fellow reflects his sustained impact on the mathematical community, both through teaching and through his contributions to mathematical literature.
Contributions to Mathematics
Essay on Louis de Branges’ Proof of the Bieberbach Conjecture
Korevaar’s most widely cited contribution is his essay on the proof of the Bieberbach conjecture by Louis de Branges. The Bieberbach conjecture, posed in 1916, concerns the coefficients of univalent (injective) analytic functions on the unit disk. It remained one of the most challenging problems in geometric function theory for over seven decades. De Branges’ proof, completed in 1984, was a landmark achievement that closed a long-standing chapter in complex analysis.
Korevaar’s essay, which earned him both the Lester R. Ford Award and the Chauvenet Prize, provided a clear exposition of de Branges’ methods. By elucidating the proof’s key ideas—such as the use of Hilbert space techniques and the theory of Toeplitz operators—Korevaar made the result accessible to a wider mathematical audience. His work helped bridge the gap between advanced research and educational materials, and it remains a valuable resource for students and researchers exploring the Bieberbach conjecture and related topics.
Personal Life
Family
Jacob Korevaar was the older brother of Nijs Korevaar, an Olympic water polo player.