After he helped solve the latest challenge you were facing and told you a story about his friend Tony, or about his post-doc who named his son Allen, or his love of babysitting his grandchildren, Allen Tannenbaum would end the visit with, “Bye, my friend.” Sadly, on the last day of 2023 family and friends gathered to say their goodbye to Allen who passed away after a brief illness in December.

Described as a “genius mathematician” by his collaborators and evidenced by the 36,000+ citations his publications received (Google Scholar, Jan. 2024), Allen’s research interests focused on computational computer vision, image processing, medical imaging, and systems control.

Recent research with collaborators at Yale University sought better treatments for Alzheimer’s Disease and was published by the journal, Nature Aging. Allen’s cancer research, Robustness of Complex Networks with Applications to Cancer Biology, was published by the Society for Industrial and Applied Mathematics (SIAM). At the time, Allen described mathematical oncology as an emerging field that had the potential to develop new treatments.

Friend and collaborator Prof. Tryphon Georgiou worked with Allen on a US Air Force funded project, Geometry of Probability Distributions with Applications to Estimation, Sensing, Surveillance, and Navigation. The AFOSR research sought to develop new geometric techniques for analyzing signals with application to navigation, surveillance, and control. Upon hearing the news of his passing, Georgiou said, “His wit, creativity, energy, love of Jeopardy, and the warmth of his heart will be dearly missed by all of us.”

Born in Brooklyn, NY, Allen’s high school classmate described him as “the smartest guy in the class” who loved the ocean (he was a surfer) and a great slice of pizza. He graduated from Columbia University with a BA in Mathematics in the midst of the Vietnam War. He quickly joined Harvard University and earned a PhD in Mathematics in 1976 when he defended his thesis, “Deformations of 1-Cycles and the Chow Scheme.”

After graduation from Harvard, Allen dipped his feet in electrical engineering and held faculty positions at institutions in Switzerland, France, Israel, and Canada. Allen joined the Department of Computer Science at Stony Brook University (SBU) in 2013 and was also affiliated with SBU’s Department of Applied Mathematics and Statistics. At SBU, Allen excelled and after two years the State University of New York Board of Trustees named him a SUNY Distinguished Professor. Becoming a SUNY Distinguished Professor was only one of many well-deserved honors. Allen was also named a Fellow by IFAC, IEEE, and the Japanese Mathematical Society. 

As someone said, “It was never boring when Allen was around.” Allen Tannenbaum was a mathematical force of kindness whose legacy and excitement reached beyond Stony Brook University.  

Memories from Colleagues

Allen has touched many hearts. He was so passionate about his work that he often insisted on explaining to me what he was doing. I loved his humor. He pretty much had a joke about everything. I remember last year, he sent me a picture with a cleaning crew saying that he had found a new career! We will all miss him.  –Samir Das, Chair, Department of Computer Science

I first met Allen at Ben-Gurion University, Israel, in 1984 when he joined the Department of Mathematics and Computer Science. I was immediately very impressed by his intellect and cheerful disposition. He moved to Stony Brook University in 2013 as a joint faculty in Computer Science and AMS Departments and has been a tremendous asset especially in research. It was a privilege collaborating with Allen on a paper titled,” Volume Exploration Using Multidimensional Bhattacharyya Flow” that was published in 2021 in the IEEE Transactions on Visualization and Computer Graphics. Allen will be sorely missed. My heartfelt condolences to the family. –Arie Kaufman, SUNY Distinguished Professor, Department of Computer Science

I was in two PhD exams with him. His comments were always on the mark, yet they were lighthearted and helpful.  May he rest in peace. He was a good person and dear colleague. He will be missed. My deep condolences to his family. – Klaus Mueller, Interim Chair, Department of Technology and Society; Professor, Department of Computer Science, Stony Brook University

Allen has been an amazing colleague, with seemingly unbounded energy and zest for mathematical research. He was always eager to engage students and colleagues in research discussions, and these were always entertaining, with his humor and wit sprinkled throughout a mathematically deep and idea-rich discourse.  We had started some discussions on geometric problems of mutual interest, for which he had unique perspectives; I regret that we did not have the opportunity to pursue these collaborations further, as I really enjoyed every discussion I had with Allen, about any topic.  He will be sorely missed. –Joseph S. B. Mitchell, SUNY Distinguished Professor and Department Chair, Applied Mathematics & Statistics

Allen's pioneering work in image understanding was a must read during my PhD study, I really learned positions after earning my PhD. He was always very nice and often gave insightful advice. He will be missed by the community and may he rest in peace. –Haibin Ling, Professor, Department of Computer Science, Stony Brook University

Allen submitted funding proposals like he was an assistant professor hoping for tenure. He never gave up. He was driven to find better ways to treat and diagnose diseases. His emails always consisted of a request and then an opinion on the latest Jeopardy host or his picks for NFL playoff games. May his memory be a blessing.  –Christine Cesaria

The news of Allen's passing is deeply distressing, and I extend my heartfelt condolences to his family. His significant contributions to medical imaging through advanced mathematics have profoundly influenced my work. His application of complex analysis and PDE for conformal cortical brain mapping sparked my own development of conformal brain mapping using spherical harmonic maps. Similarly, his utilization of optimal transportation in image registration, grounded in Brenier's polar decomposition theorem, motivated me to create a geometric variational method for solving optimal transportation problems. In my CSE528 course this term, I discussed his algorithm with the students, highlighting that while his OT algorithm is mathematically verified in two dimensions, the proofs for higher dimensions have remained an open question for many years. His departure is a tremendous loss not only to our department but also to the broader community. –David Gu, Professor, Department of Computer Science, Stony Brook University