# Welcome Courant Institute Alumni!

## Courant in the News

### NYU Courant Mourns the Loss of Professor Jerry Percus

Our colleague Jerry Percus passed away on March 7 at the age of 94. Jerry came to the Courant Institute in 1958, after obtaining his doctorate at Columbia and working for several years at the Stevens Institute of Technology. Jerry was internationally recognized for his pioneering work in statistical mechanics and combinatorics, and made seminal contributions to our understanding of fluids and biomathematics.

In addition to the famous Percus-Yevick Equation for the radial distribution function of fluids, he alone or jointly with students and coworkers, made important advances in all aspects of statistical mechanics. He was the first (or among the very first) to study "consistency" of approximate one and two particle classical distributions and quantum density matrices. This led to the Percus-Yamada condition in the former. He derived and solved equations for the velocity correlation function of fluids. He was the acknowledged master of the statistical mechanics of non-uniform fluids. His analysis of non-isotropic fluids in terms of appropriately designed isotropic ones contributed much to this subject.

In recent decades Jerry's interests turned to pioneering studies in biomathematics, in particular genome analysis and developmental biology. Many of his papers were in collaboration with his late wife, Ora. Jerry's unique and highly creative perspective on a wide range of problems in physics, mathematics, and biology will be greatly missed.

### NYU Courant Mourns the Loss of Professor Andrew J. Majda

Andrew Joseph Majda passed away on March 12, 2021 at the age of 72.

Renowned for both his theoretical contributions to partial differential equations and his applied work in diverse areas such as asymptotic methods, numerical methods, scattering theory, shock waves, combustion, incompressible flow, vortex motion, turbulent diffusion, and atmosphere ocean science, Andy Majda made a number of seminal contributions in mathematics and physics. One of the most notable is the Beal-Kato-Majda theorem, which limits the possibility for singularities in inviscid, incompressible fluid flow. Andy’s primary research interests were in modern applied mathematics in the broadest possible sense merging asymptotic methods, numerical methods, physical reasoning, and rigorous mathematical analysis.

Andy was born on January 30, 1949 in East Chicago, Indiana. He earned his Bachelor of Science degree in Mathematics from Purdue University (1970) and his Ph.D. in Mathematics from Stanford (1973). His doctoral dissertation was entitled “Coercive Inequalities for Nonelliptic Symmetric Systems.” Andy first joined the NYU Courant Mathematics Department as a Courant Instructor in 1973 and was here for just two years before moving on to faculty appointments at UCLA, UC Berkeley, and Princeton. NYU was a special place for Andy, and he returned in 1994 as the Samuel F. B. Morse Professor of Arts and Sciences in the Mathematics Department at Courant and remained here since then. He retired on January 1, 2021 and became Professor Emeritus of Mathematics.

As a pioneering theoretical and applied mathematician, Andy consistently received scientific recognition throughout his career. One of his earliest honors was as plenary speaker at the first ever International Council of Industrial and Applied Mathematics (ICIAM) in Paris in 1987. Most recently, in 2016, Andy received the Leroy P. Steele Prize for seminal contribution to research, which is awarded by the American Mathematical Society (AMS). He received the Lagrange Prize of ICIAM, the Norbert Wiener Prize of the AMS and the Society of Industrial and Applied Mathematics (SIAM), the National Academy of Sciences Prize in Applied Mathematics and Numerical Analysis, the John von Neumann Prize of SIAM, and the Gibbs Prize of the AMS. Andy was elected as a member of the National Academy of Sciences, a fellow of the American Academy of Arts and Sciences, and a fellow of both the AMS and SIAM. Twice he was awarded the Medal of the College de France, and he was elected as a Fellow of the Japan Society for the Promotion of Science. He received Honorary Doctorates from Fudan University, China Northwest University, and Purdue University, as well as The New York City Mayor's Award for Excellence in Mathematical, Physical, and Engineering Sciences.

In addition to his outstanding research, Andy was a devoted PhD advisor to thirty doctoral students, a mentor to over thirty postdoctoral researchers, and he inspired many collaborators and others in the mathematical sciences community. His published books include Compressible Fluid Flow and Systems of Conservation Laws in Several Space Variables (Springer-Verlag), Vorticity and Incompressible Flow with A. Bertozzi (Cambridge University Press), Lecture Notes for the Courant Lecture Note Series of the AMS. Other published works include the Introduction to PDE’s and Waves for the Atmosphere and Ocean, the CRM monograph series on Information Theory and Stochastics for Multiscale Nonlinear Systems, with M. Grote and R. Abramov, all published by the AMS, and Nonlinear Dynamics and Statistical Theories for Basic Geophysical Flows with Xiaoming Wang published by Cambridge University Press. His newest book with John Harlim, is entitled Filtering Complex Turbulent Systems and was published Cambridge University Press.

Andy made major contributions to NYU, locally here at the NYU New York campus and overseas. In his years at the Courant Institute, Andy created the Center for Atmosphere Ocean Science (CAOS) with eight multi-disciplinary faculty to promote cross-disciplinary research with modern applied mathematics in climate modeling and prediction. Later, he founded NYU Abu Dhabi’s Center for Prototype Climate Modeling and served as its head and Principal Investigator. More recently, Andy’s research interests included multi-scale multi-cloud modeling for the tropics, stochastic and statistical modeling for climate, and novel mathematical strategies for prediction and data assimilation in complex multi-scale systems.

Andy is survived by his wife of 46 years, Gerta Keller, who is a Professor of Paleontology and Geology in the Geosciences Department of Princeton University. Full of energy and ideas, Andy was greatly influential at the Courant Institute and in the math community and will be dearly missed by all of his colleagues and friends.

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## Alumni News

### Honoring Women in Mathematics

July 06, 2016**Lisa Fauci**, PhD Math '86 and professor of mathematics at Tulane University, was chosen to deliver the 2016 Kovalevsky Lecture "for her pioneering contributions to mathematical and computational modeling of aquatic locomotion, microorganism motility and fluid dynamics of human reproduction."

### Guy Story, M.S. Computer Science '80, speaks at NYU Entrepreneurs Festival

March 15, 2016**Guy Story**, MS Computer Science '80, in his keynote talk with Josh Brunstein of Bloomberg Businessweek at the Fifth Annual NYU Entrepreneurs Festival. Story, who was founding CTO of Audible, Inc. and is now General Manager for Automotive, Alexa Voice Services, has primary responsibility for bringing Alexa, the voice service that powers Amazon Echo and other devices, to the automotive sector.

(Photograph by Remya Thomas)

### Mikael Rechtsman receives the Alfred P. Sloan Research Fellowship in Physics

February 25, 2016Mikael Rechtsman, a Courant Instructor from 2008 to 2010, has been awarded the Alfred P. Sloan Research Fellowship in Physics. Now an assistant professor of Physics at Penn State University, Rechtsman's research seeks to understand photonics, the science of light. For more information, see the news release from Penn State University.

### When a Man Loves a Supercomputer

February 23, 2016In the Spring 2016 issue of the NYU Alumni Magazine (p.13), Emeritus Professor Peter Lax **(Ph.D., 1949)** recounts the events of May 1970, when a group of students took over Warren Weaver Hall and the institute's prized CDC 6600 supercomputer.

### Lisa Braden-Harder M.S. Computer Science '91 Receives Innovation, Leadership Award

April 24, 2015Lisa Braden-Harder, CEO of Appen, a company selling highly specialized data sets that help machines learn to read, listen, and speak in 150 different languages, received the Small Business Innovation and Leadership Award at the 11th annual Connecticut Technology Council's Women of Innovation awards program. According to the press release, Ms. Braden-Harder was recognized for leading her company through an IPO on the Australian stock exchange earlier this year. She started the Butler Hill Group in 1993 before merging it with Australian-based Appen in 2010. The company now reaches more than 50 countries, with offices in San Francisco and Seattle as well as Europe and Asia, and employs 150 people. In addition to earning an MS in computer science from Courant in 1991, she received a BS in computer science from Purdue University in 1982.

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